[PATCH] [mep] delete unused constraint-related macros and functions

mep uses {constraints,predicates}.md and #if 0'd out the old macro versions. In the interest of not keeping dead code around, I'd like to delete these. I think this falls under the obvious rule, so I'll commit this in a couple of days after waiting to hear from DJ. Tested by building mep-elf.

Re: [PATCH] [mep] delete unused constraint-related macros and functions

That's fine with me.