Upgrade firebase lib from 1.0.11 to 2.2.4. No longer accidentally open source (see #4).
Upgrade firebase lib from 1.0.11 to 2.2.4.
No longer accidentally open source (see #4).

lynnshahuang/mathdown,martindale/mathdown,lynnshahuang/mathdown,lynnshahuang/mathdown,martindale/mathdown,martindale/mathdown