An Ant build script, and some typographical tweaks?

Hi Ricard,

While writing a couple of sketches with Geomerative (which don't look like their going to get finished any time soon), I've

1. Created an Ant script for building Geomerative (I'm afraid I couldn't get the makefile to work on Windows)
2. Addressed what appear to be a couple of typographical issues with the documentation.

Since I don't anticipate making any further tweaks, I thought it was worth making you aware of these changes at this stage in case you're interested in pulling some or all of them.

Best wishes,

Antony