[Qt] Qt 4.5.XX is default

[zeljko]

Hi all,
As of lazarus svn rev. 21913 (21914 win32 dll) Qt-4.5 is default.
Qt-4.3 and Qt-4.4 are not supported anymore.
Also this change needs latest bindings v. 1.72 because of *_hook_hook_* 
changes.

zeljko