* Bump [watch-]mono to master to get fix for #43658.
https://bugzilla.xamarin.com/show_bug.cgi?id=43658
* [mtouch/mmp] Fix build after breaking cecil update in mono.
Also use mono's cecil instead of our own cecil submodule for mtouch.
* Bump [watch-]mono to get compilation fixes after cecil bump in mono.
* Remove cecil submodule, we only use the one in mono now.
mtouch only uses Xamarin.Mac to read plists, so change to use
our purely managed plist reader in Xamarin.MacDev instead.
That makes us able to change mtouch to be a normal command-line
executable (and project).
Which makes it logical to not mkbundle mtouch anymore,
it executes just fine with the system mono (and there's
no code to protect anymore either).
And since mmp and mtouch share some files, do the same
for mmp.