v0.2

• removed api.Script type in favor of good old strings
• added pulling images from repository when doing incremental build
• build forces clean build by default
• major refactoring in the way scripts are installed
• added support for ONBUILD based Docker images
• major refactoring to support different STI build strategies
• added --contextDir option to allow application exists in
  sub-directories
• fixed build when image had USER defined
  (https://bugzilla.redhat.com/show_bug.cgi?id=1185730)
• added output from failing container (during sti build)
  (https://bugzilla.redhat.com/show_bug.cgi?id=1182464)
• various fixes and improvements to documentation