improved cmake configuration:    . the default build type is now set in an improved way      (before CMAKE_BUILD_TYPE has been set to CMAKE_BUILD_TYPE      -> now CMAKE_BUILD_TYPE is set to Release iff CMAKE_BUILD_TYPE is not defined)    . improved the compiler flags:      before, regardless of the CMAKE_BUILD_TYPE cmake always configured a debug build      --> fixed
improved cmake configuration:
   . the default build type is now set in an improved way
     (before CMAKE_BUILD_TYPE has been set to CMAKE_BUILD_TYPE
     -> now CMAKE_BUILD_TYPE is set to Release iff CMAKE_BUILD_TYPE is not defined)
   . improved the compiler flags:
     before, regardless of the CMAKE_BUILD_TYPE cmake always configured a debug build
     --> fixed

     SET(CMAKE_CXX_FLAGS "-Wall -pedantic")       # base flag set
     SET(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -g") # addon for release-with-debug-info
     SET(CMAKE_CXX_FLAGS_RELEASE "-O3")           # addon for release
     SET(CMAKE_CXX_FLAGS_DEBUG  "-O0 -g")         # addon for debug

   . removed linking with 'pthreads' - not required

viennafvm/viennafvm-dev,viennafvm/viennafvm-dev