TeX Reader: Improved error messages
TeX Reader: Further improvements to error handling
TeX reader: replaced 'unary' with 'phantom'.
TeX reader: Rewrote ctrlseq and oneOfCommands.

ctrlseq now checks for notFollowedBy letter only in the case
of alphabetic control sequences.

That allows us to simplify oneOfCommands to use ctrlseq.
Removed some unhelpful error messages.

(The names are too internal to this package to be helpful
to users.)
Improved 'escaped'.

Now, the input

    \John

yields a better message, with information about all the things it
was looking for, not just the escapes.
Removed trailing whitespace
TeX Reader: Fixed parsing \phantom
Added tests for \phantom
Optimised instruction lookup
Fixed scope of try in oneOfCommands
TeX Reader: Improved performance of binomCmd
TeX Reader: Moved expensive enclosure function closer to bottom of lookup list
TeX Reader: Improved performance of operator function
TeX Reader: Remove uncessary try from basicEnclosure
TeX Reader: Removed no longer needed functions
Merge pull request #55 from mpickering/master

TeX Reader: Improved error messages