Fix RPM lint problem.

The timestamp embedded in the python bytecode file (mtime of
original source in 2006) isn't equal to the mtime of the installed
source file (now), which will force the interpreter to recompile
the .py source every time, ignoring the saved bytecode.

This patch should fix it by moving compilation to the install
phase.
Bump version to 1.2.18.
Update mftrace URL.
The calls to p.add_option() for --potrace and --autotrace have no action
attributes. Due to this some options ()for example, --noround) are always set
to defaults in mftrace-1.2. My patch fixes this issue. Also, it removes
redundant empty parameters for p.add_option() and fixes the issue with calling
fontforge which now lacks -usage option.