Fix warnings and errors (from some platforms / compilers) for C++

Switch compilation C++ standard to gnu++0x, required for strdup on cygwin.
Fix const char* conversions. 
Add space before PRIxxx constants to fix compilation on gcc 4.7 (not tested on actual gcc 4.7 but should reduce number of errors significantly)
Convert unsigned long long int to uint64_t in mfs_fuse.cc and use proper PRIu64 format for printf (fixes warnings)
Remove some unused vars, shadowed struct and sanitize printf format strings.
Printf format fixes for C++ ISO. 
Type definition fix for array inialization.