Faster base2dec Function

This is a fast replacement for base2dec. It has the same syntax as base2dec and does not require compiling.

base2dec is a nice function but slow for large arrays and quite RAM hungry.
This version is a lot faster and minimizes RAM usage. It has the same input-output behavior as base2dec.

To make use of this improvement, just replace all your base2dec calls with nbase2dec.

Included are two files: nbase2dec.m and fbase2dec.m

nbase2dec has the same error checks as base2dec
fbase2dec skips error checks to be a little faster