Latex mods

* <del>Removes console escapes for latex and sphinx converters</del>
* Add heading levels to latex converter
* Allow explicit definition of environment to latex converter

tested with https://gist.github.com/afb57a96d83f53dca3c7.git

Update:
 * Convert console ansi colors to latex markup
 * use Verbatim (fancyvrb) environment instead of original verbatim
 * add additional color definitions to latex base templates