- Remove limitation on OS.
- Add search for Mac OS X developer tools locations by using `xcrun` instead of trying to guess paths.
- Add search for locations based on path of `$GIT_EXE` (set by `lib/theme`).
* lib/helpers: use `$OSTYPE` instead of `$(uname)`
* plugins/osx: use `$OSTYPE` instead of `$(uname)`
* plugins/boot2docker: use `$OSTYPE` instead of `$(uname)`
* plugins/python: use `$OSTYPE` instead of `$(uname)`
* plugins/base: use `$OSTYPE` instead of `$(uname)`
Alsö, use `[[` instead of `[` as the former has less insane argument handling being shell syntax rather than a builtin command that must emulate being a real binary
* completion/brew: use `$OSTYPE` instead of `$(uname)`
* completion/git: use `$OSTYPE` instead of `$(uname)`
Alsö, use `[[` instead of `[`.
* completion/fabric: use `$OSTYPE` instead of `uname`
* theme/demula: use `$OSTYPE` instead of `$(uname)`
* theme/rana: use `$OSTYPE` instead of `$(uname)`
* simplify git completion to use system-provided completions only
* support ubuntu git completion
* only search non-system paths
* only operate on macos.
* no need to return 1 in a plugin
* make alias test happy
* make alias test happy
* make alias test happy
* pass exit code when capturing expected errors
* slightly more understandable code structure
* make better use of the new logging feature
