[lecture_comparison][rational_expectations] \argmax Issue

[shlff]

Dear @mmcky , I find another issue:

• \argmax is not compiled in an equation of lecture rational_expectations

Please see the following (left: MYST, right: RST)

[mmcky]

grr -- not that issue again. \argmax is my nemisis :-). Thanks @shlff -- it's a mathjax configuration issue.

[mmcky]

This is fixed in #35 waiting for merge until rst is frozen.