[Interfaces] Qt5-compatible LC_EXPORT_PLUGIN.
[CSTP] Removed obsolete includes.
[CSTP] Qt5 compatibility.
[Poshuku] Qt5 compatibility.
[Overall] Added Qt5 macros to FindLeechCraft.cmake.

Particularly, FindQtLibs, Qt{WrapUi,AddResources}, and finding Qt4.
[Overall] Don't find Qt4 in InitLCPlugin.