Merge pull request #109 from rhart/master

Add a File renderer (closes #108)
formatting.
Ratpack now requires Java 7.
Rename “workerThreads” to “mainThreads”.
Introduce a mechanism for executing blocking operations (closes #114).
debugging heroku deployment issue.
debugging heroku deployment issue.
Cleanup after heroku debugging.
#104 - implementation of handlebars support finished, still need to add the docs
Merge remote-tracking branch 'origin/master'

Conflicts:
	ratpack-test-support/src/main/groovy/org/ratpackframework/test/DefaultRatpackSpec.groovy
Add some changes that were omitted in the previous commit.
minor generic fix.
whitespace
Adding "modified since" support to FileRenderer
Refactoring common file handling logic
Merge branch 'master' of https://github.com/rhart/ratpack