This name is a little bit better I think, and it will be nice to have a
distinction between this utility and the 'file' kind of buffer.

The editor now loads fonts from /usr/ instead of the current working
directory. Since they are gzipped the font loading code now uses zlib to
read from the files.

These fonts in particular were installed with `make install-psf` from
the Terminus makefile, however the location may vary from system to
system.

For whatever reason lines were called rows in the code, so this refactor
changes that name everywhere. The name 'row' is still used in some
places to refer to the unit of height in the screen.