* cleaned up compiler options related code in CMake
* moved cmake_minimum_required() and raised to latest 2.8.x version
* use proper compiler version check / print compiler version
* fixed linking of sanitized builds
* added proper version checks to newer Clang warnings and enabled them / moved tinyxml_objs flags to proper compiler
* disabled -Wdeprecated-declarations for Clang
* compileroptions.cmake: removed unnecessary check for clang++ existence - CMAKE_CXX_COMPILER_ID is determined by CMake
* printInfo.cmake: removed unnecessary message for ANALYZE_ADDRESS - LSAN is part of ASAN and enabled by default
* cleaned up if() comparisons in CMake
* added/adjusted TODOs
* fixed compilation of OSS-Fuzz clients
* added preliminary CMake target for fuzz-client - also added *_sanitized targets of dependencies (only available with Clang)
* added oss-fuzz build to Travis CI