All, this is a first attempt at refactoring `dev/run-tests` into Python. Initially I merely converted all Bash calls over to Python, then moved to a much more modular approach (more functions, moved the calls around, etc.). What is here is the initial culmination and should provide a great base to various downstream issues (e.g. SPARK-7016, modularize / parallelize testing, etc.). Would love comments / suggestions for this initial first step!

/cc srowen pwendell nchammas

Author: Brennon York <brennon.york@capitalone.com>

Closes #5694 from brennonyork/SPARK-7017 and squashes the following commits:

154ed73 [Brennon York] updated finding java binary if JAVA_HOME not set
3922a85 [Brennon York] removed necessary passed in variable
f9fbe54 [Brennon York] reverted doc test change
8135518 [Brennon York] removed the test check for documentation changes until jenkins can get updated
05d435b [Brennon York] added check for jekyll install
22edb78 [Brennon York] add check if jekyll isn't installed on the path
2dff136 [Brennon York] fixed pep8 whitespace errors
767a668 [Brennon York] fixed path joining issues, ensured docs actually build on doc changes
c42cf9a [Brennon York] unpack set operations with splat (*)
fb85a41 [Brennon York] fixed minor set bug
0379833 [Brennon York] minor doc addition to print the changed modules
aa03d9e [Brennon York] added documentation builds as a top level test component, altered high level project changes to properly execute core tests only when necessary, changed variable names for simplicity
ec1ae78 [Brennon York] minor name changes, bug fixes
b7c72b9 [Brennon York] reverting streaming context
03fdd7b [Brennon York] fixed the tuple () wraps around example lambda
705d12e [Brennon York] changed example to comply with pep3113 supporting python3
60b3d51 [Brennon York] prepend rather than append onto PATH
7d2f5e2 [Brennon York] updated python tests to remove unused variable
2898717 [Brennon York] added a change to streaming test to check if it only runs streaming tests
eb684b6 [Brennon York] fixed sbt_test_goals reference error
db7ae6f [Brennon York] reverted SPARK_HOME from start of command
1ecca26 [Brennon York] fixed merge conflicts
2fcdfc0 [Brennon York] testing targte branch dump on jenkins
1f607b1 [Brennon York] finalizing revisions to modular tests
8afbe93 [Brennon York] made error codes a global
0629de8 [Brennon York] updated to refactor and remove various small bugs, removed pep8 complaints
d90ab2d [Brennon York] fixed merge conflicts, ensured that for regular builds both core and sql tests always run
b1248dc [Brennon York] exec python rather than running python and exiting with return code
f9deba1 [Brennon York] python to python2 and removed newline
6d0a052 [Brennon York] incorporated merge conflicts with SPARK-7249
f950010 [Brennon York] removed building hive-0.12.0 per SPARK-6908
703f095 [Brennon York] fixed merge conflicts
b1ca593 [Brennon York] reverted the sparkR test
afeb093 [Brennon York] updated to make sparkR test fail
1dada6b [Brennon York] reverted pyspark test failure
9a592ec [Brennon York] reverted mima exclude issue, added pyspark test failure
d825aa4 [Brennon York] revert build break, add mima break
f041d8a [Brennon York] added space from commented import to now test build breaking
983f2a2 [Brennon York] comment out import to fail build test
2386785 [Brennon York] Merge remote-tracking branch 'upstream/master' into SPARK-7017
76335fb [Brennon York] reverted rat license issue for sparkconf
e4a96cc [Brennon York] removed the import error and added license error, fixed the way run-tests and run-tests.py report their error codes
56d3cb9 [Brennon York] changed test back and commented out import to break compile
b37328c [Brennon York] fixed typo and added default return is no error block was found in the environment
7613558 [Brennon York] updated to return the proper env variable for return codes
a5bd445 [Brennon York] reverted license, changed test in shuffle to fail
803143a [Brennon York] removed license file for SparkContext
b0b2604 [Brennon York] comment out import to see if build fails and returns properly
83e80ef [Brennon York] attempt at better python output when called from bash
c095fa6 [Brennon York] removed another wait() call
26e18e8 [Brennon York] removed unnecessary wait()
07210a9 [Brennon York] minor doc string change for java version with namedtuple update
ec03bf3 [Brennon York] added namedtuple for java version to add readability
2cb413b [Brennon York] upcased global variables, changes various calling methods from check_output to check_call
639f1e9 [Brennon York] updated with pep8 rules, fixed minor bugs, added run-tests file in bash to call the run-tests.py script
3c53a1a [Brennon York] uncomment the scala tests :)
6126c4f [Brennon York] refactored run-tests into python