"cumtime" wasn't compatible with my old CPython

Just working with whatever comes from FC18 repos.  I have "cumulative"
but not "cumtime"; think just older version.
missing a return statement in the rewrite phase.
removed printing code from the function generator
have scipy and numpy support instead of cvxopt
added csc matrices for C code gen
new coeff is ready to merge
constant folding is completed. fixed some minor bugs.
Merge pull request #23 from chinasaur/backcompat/1

use "cumulative" instead of "cumtime" for backwards compatibility
added example directory. fixed small bugs to get examples work. did not check for correctness