OSX Packaging: py2app

[Antoine Martin]

Packaging should be done with: ​py2app

Server seems to work OK on OSX (after installing all the required dependencies using macports), but we need to add authentication against the password database (this may also work for BSD/Solaris):
​pykpass

So we may need a new server option: "password_auth_module" = [pam|pykpass]. And provide a common wrapper interface for both.

We will also need to load the list of X applications from somewhere... and OSX does not follow the freedesktop spec, so we may just test for a few (xterm, ...) and create these "*.desktop" files in ~/shifter/server/menu/ on first start.

TigerVNC can be built on OSX, but I cannot find any ready-made images, see this:
​tigervnc-devel message

nxproxy can be built with macports' help (libpng, jpeg):
​nxproxy-apple

xpra: client and server both build fine (with ​this simple patch)
But only the client is usable... (keymap issues for server)