Log Message:
Update to 0.6.5.2

changes:
0.6.5.2
 - Fixed serious bug handling commands.
   Support \not\in.
   Added tests.
0.6.5.1
 - Support \not\subset, etc. Closes #22.
 - Added nsubset, nsubseteq, nsupset, nsupseteq. Closes #23.
0.6.5
 - texMathToPandoc: Use $$ delimiters for display math in fallback.
 ( #22 => https://github.com/jgm/texmath/issues/22 )
 ( #23 => https://github.com/jgm/texmath/issues/23 )