Add to clean.
Nodesize configuration in test.
User message regarding variable importance.
Fix of division by 0 resulting into Float.NA
Fix of missing assignment leading to saving old CM.
A simple graph to show variable importance.

Spencer's code generating graph refined into two parts:
 - JS code providing a function drawing a SVG
 - CSS defining visuals of graph

The HTML code has to include JS as well as CSS (via <style
scoped>@import url('url')</style>

D3 library replaced by packed version to safe the network traffic ;-)
Removed nodesize since we have already min_rows param.
Var importance computed in parallel over all variables.
Tree stats.

Tracking min/max/mean for depth/leaves on the fly.
add -b BRANCH and -d TESTDIR args to runner_setup.sh, args passed from the top level runner*sh scripts. (and in jenkins as jenkins downstream parameters)

move syn_datasets under sandbox (SYNDATASETS_DIR is used in all tests, so invisible except for parity.pl was hardwired, now gets datasetsDir param..and a couple of tests had some hardwired syn_datasets..fixed)
Merge branch 'master' of github.com:0xdata/h2o
Fix in computing tree stats for GBM trees.
added some Exec2 testing and more stressful gz compression ratio
Added some basic operations like logical AND/OR
Graph Java API little bit polished.
Var imp name tooltip.
Fix in computing tree stats.
Merge remote-tracking branch 'origin/master' into drf2
WIP Adding cut method to ExecQuery2
Merge branch 'master' of https://github.com/0xdata/h2o