Merge pull request #26 from gmt/master

2nd try: .gitignore, fix active branch, & drop superfluous stuff
Bump version to 0.3.0
Gittle.rm_all: cache index property value so our changes persist

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>
Gittle: add create_orphan_branch API to emulate git checkout --orphan (WIP partial implementation)

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>
Gittle.create_orphan_branch: implement optional empty_index parameter

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>