Share common tree-building driver logic

New file SharedTreeModelBuilder has a lot of common stuff between GBM
&DRF.
Switch test_tree.csv to Earl's version.
(fix PCA from using AppendableVec's)
Mid giant GBM hack
GBM mid-hack; ESL2 pg 387, Steps 1-2biii

Most of GBM done right.
Needs step 2biv, nice pretty-printers for whole (small) datasets.
compile errors
Added glm for fluid vecs.
Merge branch 'master' of github.com:0xdata/h2o
Added glm for fluid vecs.
Merge branch 'master' of github.com:0xdata/h2o
Merge branch 'master' of github.com:0xdata/h2o
Minor changes in GLMTest2 (Which is commented out for now anyways).
prostate+GBM working, not cars

Cars.csv as missing data, catagoricals, and a response klass (7 cylinder
cars) which never appears (although 3-8 cylinders do appear).  Currently
failing on building a tree for cylinder 7.
GBM looks like its working

Handles covtype, cars, prostate, & a few more with a variety of
arguments
Missing response col cutout
More missing NPE check
sort'n this evil dataset

has really bad split choices, for having many cols that have equal
values & NAs
switch back to master for h2o_release_tests jar download
put the new col summary failing case last in the list
make Runit tests single machine only, until import file/dataset issue gets addressed.
i think this will do airlines rf from hdfs at 0xdata
say 0xcustomer is the username on the found cloud (/home/0xcustomer used when resolving pathnames for buckets)