Improve fallbacks for missing markers.

Allow disabling of URL rewriting for SSML output.

Fix linking error, didn't expose Types.hs

Export C APIs from files defining underlying functions.

Remove dead code.

Output converted webpage.

Partially fix segfaults, enough to continue on.

Still questions remain, and there's broken C APIs exposed.

Switch to C for I/O. FIXME currently segfaults.

Draft C Bindings, so C APIs can be used for I/O.