the environment handling code was showing its age. just because environ is a char...

the environment handling code was showing its age. just because environ is a char** array doesn't mean we must exclusively operate on such. convert to a red-black tree, manipulate as desired, then flatten to array. potentially overkill for the current operations, but reading the tea leaves i see that more manipulations are desired. ok tb (and some thought provoking disagreement from martijn)