mlaunch tests: do not require arbiter be last in the replset.
test_mlaunch: test large (12 node) replsets.

With and without arbiters.

Currently fails, because all nodes have the default votes: 1.
mlaunch: Allow over 7 nodes.

All nodes over the 7th (or 6th if --arbiter) get votes: 0.

Fixes #123.
Merge pull request #125 from devkev/feature-arbtest

mlaunch tests: do not require arbiter be last in the replset.
renamed "other" group label for --group-limit to "all others combined" to be more specific.
added new parameter --stacked to histogram plots to switch between stacked/nonstacked bar histograms.
pattern extraction from loglines. can be used to group by "pattern" in mplotqueries.
added tests for pattern extraction. Fixes #129.
Merge branch 'develop' of github.com:rueckstiess/mtools into feature-129-pattern
Merge branch 'develop' of github.com:rueckstiess/mtools into develop
Merge branch 'feature-129-pattern' into develop
Merge branch 'feature-123-novotes' of github.com:devkev/mtools into devkev-feature-123-novotes