v0.5 Release (animated gif lolcommits)

Preparing for v0.5 release, [see this issue](https://github.com/mroth/lolcommits/issues/113) for details;

progress so far
 - [x] update changelog and version
 - [x] investigate issues with wacaw binary on latest MacBook air (@matthutchinson)
 - [x] build, test and release [VideoSnap](https://github.com/matthutchinson/videosnap) as a separate command line app
 - [x] integrate VideoSnap into lolcommits
 - [x] all tests pass on build machine without errors
 - [ ] push built gem to rubygems
 - [ ] push git tags to github
 - [ ] manually tag "release" via github feature and add notes from changelog