[dev-util/kdevelop-clang] QA issues

* use kde4-base eclass, reduces duplicated code
* remove SLOT, moves to 4
* shorten DESCRIPTION
* add debug USE flag
* fix dependencies: sort + require at least llvm-3.4

Package-Manager: portage-2.2.10
[profiles/updates] dev-util/kdevelop-clang slotmove 0 -> 4