TeXMath Reader: Added symbol type lookup to unicode parsing
MathML Writer: Explicitly write accent=False for characters which could be interpreted as accents
TeXMath Reader: Added recognition of escaped space in text environment
MathML Reader: Potential fences which are not actually fences are now constructed with the correct type
Standardised sqrt behavior.

Some readers and writers were expecting arguments in different
positions. It is now standardised across all modules - the correct order
is index followed by base (the same order as in latex). This differs
from the MathML ordering (which is base followed by index).
Updated cabal file
Merge pull request #53 from mpickering/master

Fixes to bugs highlighted by round trip testing