package directory was showing up in dmg file

Correctly supports application name and branding changes

To debug travis failure

Changing the directory prior to invoking macdeployqt so it can find the app bundle.

-qmake rename installer output

Switch to cd into release and then back to run macdelpoyqt

Would fail every other time

Also fix problem with incorrect symbolic link to plugins

hdiutil called from inside macdelpoyqt was failing. Managed to get it
not to fail by changing layout to SPUD instead of GPTSPUD.
Unfortunately know idea why this works!

Handles case where multiple versions of QT are installed on machine.