[mtouch/mmp] Use full path to mono.

tools/mmp/mmp.in

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-mono --debug @XAMARIN_MAC_PREFIX@/lib/mmp/mmp.exe "$@"
+/Library/Frameworks/Mono.framework/Commands/mono --debug @XAMARIN_MAC_PREFIX@/lib/mmp/mmp.exe "$@"

tools/mtouch/mtouch.in

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-mono --debug @MONOTOUCH_PREFIX@/lib/mtouch/mtouch.exe "$@"
+/Library/Frameworks/Mono.framework/Commands/mono --debug @MONOTOUCH_PREFIX@/lib/mtouch/mtouch.exe "$@"