Merge pull request #48 from ysb33r/master

JRubyWar, JRubyJar removed
Remove my personal bintray repo since warbler-bootstrap is now in jcenter
Remove jrubyClean which shouldn't be in base and bring jrubyPrepare back
Upgrade the base plugin to default to using the recently released v1.7.14

Fixes 49
Rolled back to jruby-complete 1.7.13 as the default version due to issues we have been seeing with 1.7.14. Added support for Warbler Bootstrap so that derived plugins can easily make use of it also allowing the user to control the version