Utility function microoptimizations

Cycle with numbers instead of ipairs and other minor tweakings in an
attempt to improve performance. The gain is honestly negligible.
Length functions microoptimizations

The functions present in length.lua are called many times... an attempt
to optimize them was sensible. The gain is negligible on PUC Lua,
though.
Various fixes.
A Harfbuzz shaper. Doesn’t actually output anything yet, as the front-end is too tied to pangocairo. Also we now need autoconf. Ugh.
Fixes some segfaults.
Various fixes, pass font options as well as PangoAttributeLists.
Beginnings of PoDoFo class.
Nearly there now.
Autoconfiscate. Will fix up the mess after this.
Pass the hbox outputting to the output layer, since it knows what the relevant shaper has provided.
Oops.
This only appeared to work before because I had a copy installed. Ugh.
Further placation of the evil build system.
Remove autojunk.
Ignore more autojunk.
Yet more autojunk.
Allow for uninstalled use.
Shell portability
Sadly we need to compile on Linux too.
The reason this worked was grotesque typecasting hackery. Using MemDocuments means we can use the swig bindings without modification.