TST: add tests for old version of numexpr
closes #5857
closes #5855
closes #5845

think you need to add numexpr < 2.0 to py2.6 build?
 yep i didn't forget ... i'm doing it now :)
 look ok to me
 cool i just want to move `skip_if_no_ne` to testing ... DRY and all ... and it'll give a more informative msg on skip
 cool
 hm getting a timeout from the redhat server ... rehashed ... let me see if that passes
 nvm
 @jreback stepping out for a bit can u merge if green? thx
 sure
 Ok I'll merge. @jreback any last words?
 sorry stepped out too

bombS away
 Crap I just undid @y-p's nosetests v pr I'm on my phone right now can't get to it ... Can do it later tonight or if someone wants to fix thats cool too
 I'll fix it.
 Thanks. Sorry about that. Don't mean to create moar werk :/
 we all clobber at one point or another. np.
