abbreviations for MT, not G

used abreviations that are found in the Mishna Torah, not the ones from the Gemara
Added Nedarim abbreviation found in the README

ndr was listed as an abbreviation for Nedarim in the README, but not in the code
wrong abbreviation for Eruvin

accidentally put re instead of er
Merge pull request #3 from menachemshapiro/master

two changes - one to js. and one to README