added several new functions to modsym_OMS_space which ultimately construct a basis of the ordinary part and compute Hecke matrices on that basis

One needs row reduction mod p^n to do this -- in a major hack, I pipe code to Pari which can do that.  Daniel's code will ultimately fix this, but I
wanted to get the ball rolling on this...
Merge branch 'master' of https://github.com/lalitkumarj/OMSCategory