Portability improvements and ease-of-use

• Add warnings for files that are missing test cases
• Add warnings for left-over test cases for removed files
• Segfault-recovery (error-status)
• Support for automatic stubbing/mocking on PowerPC
• Clang support
• Bug-fix for error/fail output in the JUnit format
• Support for -fsanitize (works best for clang, currently)
• GCC 4 portability
• Aproximate calls to real functions with variadic arguments, like printf, sprintf, fprintf in module tests