Updates polymorphic variants to variants

Polymorphic variants are a little bit more efficient than polymorphic
variants and we don't really need any of the features offered by
polymorphic variants. So this commit switches Ocamlua to use regular
variants.
Updates build files

Updates the OMakefiles to better capture the files generated by the
ocamlmklib process. In addition a rough installation command has been
created that can read some configuration variables to control where
files are installed.
Adds gitignore to VC
Updates README

Expands on the installation and build instructions for OCamLua. Switches
to use Markdown for pretty formatting on github.