Fixes for the X11 backend with XFT fonts from demo/x11_xft:
- fixed some memory leaks by destroying XFT objects during cleanup
- the function to get text width was returning the wrong value
- the clipping space of text boxes was not implemented for XFT
- misc
If XftDrawString8() is given non-ASCII UTF-8 string it fails to properly render it.
Using XftDrawStringUtf8() instead seems to be doing the right thing.
Signed-off-by: Sergiy Kibrik <sakib@darkstar.site>
