Avoid copypasta
Fix crash due to invalid memory access

The last element in a vector is size() - 1, no idea how this code even
worked.

Fixes #1
Use vercor's front() and back()

Makes the code a bit more clearer.
invalid using options
rename fontcrunch.py executable binary script to font-crunch.py
Regenerate with SWIG 3.0.2

To avoid unrelated diffs in the next commit.
Simplify the quadopt module

Take "bez" string as input and output the optimized one, instead of
reading and writing files on the filesystem.
Add a fontcrunch.optimize() that uses quadopt
Removed unused code

This also removes the "plotting" functionality (and the sipro dependency
with it), not sure if it is still wanted, though.
Spiro is not used now