Revert "Refactored interp's binop so that it uses some locals" It caused many failed tests.

This reverts commit 1508476d4dbcf39ec0b7d609b19c1b5301fb3eef.
Merge branch 'master' of https://github.com/reggiegg/GRTEAMWORK
Merge branch 'master' of https://github.com/reggiegg/GRTEAMWORK

Conflicts:
	xinterp-lazy.rkt
Merge branch 'master' of https://github.com/reggiegg/GRTEAMWORK

Conflicts:
	xinterp-lazy.rkt
UPdated tests in lazy version, and added an hour to the Readme (and edited a bit).