[Qt] Default Qt version

[zeljko]

Hi all,

1.I would like to completely remove qt43 support (or set USE_QT_43 for those 
who still needs qt-4.3.XX ?)
2.qt44 should work with USE_QT_44 (there are some diffs between qt44 and qt45)
3.Qt45 should work without USE_QT_45 (default)

So, we'll have qt45 as default (without any definition), and qt44 (with 
USE_QT_44).

Any ?

zeljko