feat(debug cljx): accept breakpoints
fix(debug): breakpoints in clj files works when launched with leiningen
fix(debugger): make breakpoint specific on filepath, not just filename

Fix Issue 273:	debugger breaks in wrong place if files have same name
refactor(debug): more logical placement of methods
refactor(debug): remove unnecessary code

- ClojureSourceLookupDirector
- ClojureSourceLookupParticipant
- ClojureSourceContainer
fix(product): Preferences > General > Appearance was throwing an exception

Fixes Issue #646
doc(README): add tip4commit widget
doc(README): fix broken jenkins image
Update CONTRIBUTING.adoc
fix(startup): prevent some code to be launched before worbench is started
chore(mvn): Version 0.27.0
chore(mvn): Prepared version numbers for 0.27.1-SNAPSHOT
Merge branch 'master' into paredit-papercuts