add support for next function: DAYS, ISFORMULA, RRI, DMIN, DMAX, DAVERAGE, DSTDEV, DSTDEVP, DCOUNT, DCOUNTA, DGET, DPRODUCT, VAR, VARP, DSUM, BITAND, BITOR, BITXOR, BITLSHIFT, BITRSHIFT, MAXIFS, MINIFS, TEXTJOIN, BESSELJ, BESSELK, BESSELY, BESSELI, NETWORKSDAYS.INTL, WORKDAY.INTL, SWITCH, ISOWEEKNUM, AGGREGATE, BINOM.DIST.RANGE, ECMA.CEILING, SHEET, SHEETS, UNICODE

Fix Bug 35408.

Update grunt to latest stable version

According to Maxim Kadushkin mocha tests was added long time ago
and not maintained.
So may to remove all togher, but for now - just update to latest.