Rationalize ttf2lff

Link against QtCore only, not QtGui;
Add FreeType error reporting;
Use Qt instead of libc for getting current date;
Fix argument handling; plug a segfault or two in doing so;
Slight reorganization here and there;

Output being unchanged is verified on a set of 130-odd TTF fonts.

XXX: Does OSX still need sys/types.h?

Signed-off-by: Tamas TEVESZ <ice@extreme.hu>
Merge branch 'master' of github.com:LibreCAD/LibreCAD