[SPARK-7262] [ML] Binary LogisticRegression with L1/L2 (elastic net) using OWLQN in new ML package

1) Handle scaling and addBias internally.
2) L1/L2 elasticnet using OWLQN optimizer.

Author: DB Tsai <dbt@netflix.com>

Closes #5967 from dbtsai/lor and squashes the following commits:

fa029bb [DB Tsai] made the bound smaller
0806002 [DB Tsai] better initial intercept and more test
5c31824 [DB Tsai] fix import
c387e25 [DB Tsai] Merge branch 'master' into lor
c84e931 [DB Tsai] Made MultiClassSummarizer private
f98e711 [DB Tsai] address feedback
a784321 [DB Tsai] fix style
8ec65d2 [DB Tsai] remove new line
f3f8c88 [DB Tsai] add more tests and they match R which is good. fix a bug
34705bc [DB Tsai] first commit