Use character size scaling factors

The bounding boxes for characters can be scaled using "cwscale" and "chscale"
to scale the width and height respectively.
Fix blink mode check

ATTR_BLINK is an attribute for a Glyph and will not be set in term.mode.
Fixed memory leak in xsettitle().
Fix signess of tdefcolor

tdefcolor() returns -1 on error, while its return type is
unsigned long. At the same time, line 1724 and 1731 are checking the
positivity of its unsigned return value.