OSX launchdaemon and homebrew formula

The OSX launchdaemon has to be moved to /Library/LaunchDaemons/. As a
result the syncany daemon will be launched once the system is started.
TODO: move the file using gradle to the specified directory.

The homebrew formula allows less experienced users to use syncany
without having to manually build it. Homebrew only accepts production
ready software, therefore we need to provide the formula. (thanks to
@tvon, closes syncany/syncany#267).
OSX: Copy launchdaemon during fake install

Copy launchdaemon to /Library/LaunchAgents during fakeinstall. Syncany
is then running in the scope of the user which is currently logged in.
Please note that the syncany daemon is not automatically started after
installation.
Merge branch 'develop' of https://github.com/syncany/syncany into feature/osx-integration