Add a config option to enable passing special macros needed to
handle the output from the mhchem texify process.
Bug: T340023
Change-Id: I3553931c252184b54e7a13938e030825e5d45e59
* Uq and Dq was mixed
* Simplify regeneration of grammar for node developers
* Speed up npm test by ignoring local test json files
Change-Id: Iec273dcc967be46d3df52260fc56f1969667e497