fix original regular expression

* it only matched one single pari of `$$`, due to the leading `^` and trailing `$`
* it was greedy, thus the additional `?`
improve regular expression

* regular expression is improved and prepared for display math
* display math seems to be not possible inside TikZ/pgfplots
add new testcase `latexInterpreter`
join with previous testcase `latexmath1`

* adapt that test case to show clearer that `FontSize` is currently neglected
* use upright differential :-)
improve ordering of test cases
Merge remote-tracking branch 'PeterPablo/fix_448_display_math' into develop

Conflicts:
	test/suites/ACID.m