Exposing the build tree. (#1017)
Exposing the build tree. (#1017)

* Exposing the build tree.

* Warning users about internal representation.

Khan/KaTeX,Khan/KaTeX,kwangkim/KaTeX,xymostech/KaTeX,kwangkim/KaTeX,kwangkim/KaTeX,xymostech/KaTeX,xymostech/KaTeX,kwangkim/KaTeX,kwangkim/KaTeX,Khan/KaTeX,xymostech/KaTeX,xymostech/KaTeX