Basic Compilation with Qt5 and OSX

This PR allows zeal to be compiled on OSX with Qt 5.1.

Mostly it fixes the assumption in preprocessor defines that if it isn't Windows then it must be Linux.
It also upgrades Quazip to the latest version which is compatible with Qt5.

The OSX compatibility is not yet good enough to be an alternative to Dash but it is useful for developing Zeal.
I am a Dash user but I might switch to Linux in a few years and I want to contribute to Zeal to make sure it can be a usable Dash replacement.