`ctx.js()`: extend `js` from bemjson (fix #73)
Merge pull request #75 from enb-make/js

`ctx.js()`: extend `js` from bemjson
tests for applyBase
Ctx preserve after `applyBase` (fix #72)
Revert "tParam: should correctly work with `applyBase`"

This reverts commit 195117437ce51511d77b2e05f3a4ddc96ea44529.

Conflicts:
	lib/bh.js