new cross platform filesystem api
FIX buffer overflow error :

[Common/Source/Draw/LKDrawVario.cpp:442]: (error) Array 'brc[32]' accessed at index 47, which is out of bounds.
[Common/Source/Draw/LKDrawVario.cpp:416]: (error) Array 'negativeBrush[16]' accessed at index 31, which is out of bounds.
add new TARGET : PCX64, only use it for debugging facility
add -std=c++0x flag & fix error
 - replace auto_ptr by unique_ptr
 - add some include <math.h> for fix missing definition of ERANGE in stl
improve runtime.log message for "Bitmap file missing"
fix Signed/Unsigned warning in "CP_2D_polygon_clip"
add missing const
new base class for CAirspace, allow to copy aispace instances, without mistake on virtual function usage.
  it's more robust, compile time error instead of runtime artefact.
replace -std=c++0x by -std=gnu++0x for compatibility with mingw32ce