[darwin] - rebrand packages and binaries to Kodi

This PR is not complete yet - but i want it to be open as a placeholder (and so that nobody doubles my work here). In general i used the @APP_NAME@ and CCompilerInfo::GetAppName where i could.

What is already done:

1. iOS rebrand is complete
 a. app id is changed to org.xbmc.kodi-ios (xbmc foundation, kodi product, ios platform)
 b. The postinstallation script of the debian package detects a side by side situation and copys the complete XBMC folder over to the Kodi folder. It also informs the user that this task my last some minutes.
 c. XBMC can live side by side with Kodi with complete seperated settings...
 d. All Binaries and Folders are either renamed to Kodi or to project agnostic strings (like XBMCHome -> AppHome)

2. OSX rebrand nearly complete
 a. The migration from XBMC data to Kodi data is implemented in the g_application.preflight (which runs a perl script) - though there is no visual feedback for the user yet (our window is not even up at that point) - and on a 4GB XBMC folder it lasts a couple of minutes on HDD. Anybody has an idea how to popup a messagebox during the copy from perl? (maybe some apple script or so?) - any input @amet or @jmarshallnz

3. ATV2 rebrand - this one is a bitch:
 a. app id is changed to org.xbmc.kodi-atv2 (xbmc foundation, kodi product, atv2 platform)
 b. The postinstallation script of the debian package detects a side by side situation and copys the complete XBMC folder over to the Kodi folder. It also informs the user that this task my last some minutes.
 c. All Binaries and Folders are either renamed to Kodi or to project agnostic strings (like XBMCHome -> AppHome)
 d. At the moment i didn't get the rebranded version to run. The problem is that all apps on ATV2 are plugins. It complains about a lot of classes which are already presented by our XBMC dylib (behaviour is undefined) - also it doesn't pick up the right principal class (so it just crashes in a loop)
e. I have no clue if we find a real solution for allowing side by side installation of XBMC and Kodi

@davilla feel free to jump in. 

Also as you can see this is not ment to be reviewed yet (needs a heap of squashing).

@topfs2 fyi ping
the env var is set here: https://github.com/xbmc/xbmc/blob/master/xbmc/Application.cpp#L1107