Added a function to commit files to avoid code duplication
Removed taglist task attachment to compile (it may be buggy)
Moved docs cleaning to the special command and moved commiting to the end of release process
Moved api docs cloning/generation to a temp dir; moved taglist task to the release first step
Updated docs
Moved release notes check to the beginning
Upgraded to sbt-assembly 0.11.0
Wrote release notes
Moved release notes check after the version setting step (otherwise it doesn't make any sense)
Minor TODOs
Fixed gh-pages cloning target dir
Show release notes when checking it precense
Minor comments fixes
Minor log fix