Fix Makefile to support PJSIP 2
Fix problems with C compiler and MS C-compiler
Fix Makefile to support PJSIP 2
Fix problems with C compiler and MS C-compiler
Fix maximum buffer length, change handling of user callback structure

Reported and proposed by Eeri Kask, TU Dresden
(Eeri.Kask@mailbox.tu-dresden.de)
Merge branch 'develop' of github.com:wernerd/ZRTP4PJ into develop
Add casts and #ifdef to address some compiler issues on iOS8 and Windows

This commit does not add new functions or other code changes.
Fix compile errors on clang/LLVM on iOS 8

Some modification to fix some warnings if using clang/LLVM compiler.
Add a small trick to keep Clang/LLVM quite

Provided by Marcus Froeschl.
Fix small typo and remove (comment) unused timer_stop function