#72 Make only variables italic in math

[Martin Geisler]

I would like the inline math markup to only make variable names italic. In particular, parenthesis and numbers should not be italic:

M{(a + b)} => (<i>a</i> + <i>b</i>)

It would be extra cool if standard function names like log, sin, cos, tan, and exp were recognized and left alone:

M{log(a)} => log(<i>a</i>)