Added strong rules to glm2.
Updated strong rules (correct expansion of beta between different lambdas (with different number of active cols).
few bug fixes in glm2 strong rules
Fixed line-search with strong-rules. Potential AIOB when comparing betas of different sizes. Added explicit expansion to full size beta (for now) when comparing gradients/betas in line-search.
Strong rules update.
Merge branch 'master' into glm_strong_rules

Conflicts:
	src/main/java/hex/FrameTask.java
	src/main/java/hex/glm/GLM2.java
GLM2 strong rules. Few fixes after merge with master.
strong rules update.
strong rules update.
strong rules update
strong rules update
Updated strong_rules to not to filter out variables once they were once included in the model (so that the variable activation is monotonic) to prevent issues with line search (had problems with having previous solution with incompatible set of cols).
As a result, the line-search code is simpler, but can run with more columns than needed, does not seem to cause significant difference though.
Merge branch 'master' into glm_strong_rules
Strong rules bug fix. Corrected move to next lambda in case line-search failed and the current lambda does not have any valid solution (possible if lambdas are too close to each other).
Added maximum allowed number of predictors to glm (currently set to 8000).
Strong rules update - few fixes to make family=gaussian case work (special case as it does not do reweighing).
Avoid NPE.
Use execImpl instead of fork.
Make params public and add size guards during sharing of layer weights and biases.
Cleanup.