Added Unicode to Ascii mapping
Added Unicode to LaTeX mapping
Added essential dictionarys for MML Parsing

EntityMap contains a list of all entities defined by the MML specification.

MMLDict contains information about all operators and their corresponding
attributes in MML.
Added additional type definitions for these files
Factored our other common tables into a shared file
Generalised ToUnicode so it can be used to lookup both ways
Added MathML Parser
Added LaTeX writer
Modified existing writers and standardised interface
Added tests
Rewrote UnicodeToLaTex and added docs
Added compatability layer in order to work with older versions of mtl