This change replaces usages of colt with commons-math3 equivalents, and makes some minor necessary adjustments to related code and tests to match.

Author: Sean Owen <sowen@cloudera.com>

Closes #2928 from srowen/SPARK-4022 and squashes the following commits:

61a232f [Sean Owen] Fix failure due to different sampling in JavaAPISuite.sample()
16d66b8 [Sean Owen] Simplify seeding with call to reseedRandomGenerator
a1a78e0 [Sean Owen] Use Well19937c
31c7641 [Sean Owen] Fix Python Poisson test by choosing a different seed; about 88% of seeds should work but 1 didn't, it seems
5c9c67f [Sean Owen] Additional test fixes from review
d8f88e0 [Sean Owen] Replace colt with commons-math3. Some tests do not pass yet.