Accept all valid UTF-16 characters in \mbox, \text, etc commands.
More precisely parse the mandatory argument for matrix environments.

A leading \hline command must come after the argument, if there is one.
Certain matrix-like environments (array, alignedat) require a mandatory
argument.
Add 287,201 test cases.

Add test cases from http://www.formulasearchengine.com/Verify%20texvc%20light
which comprise all forumlae from enwiki (at some snapshot in time).