remove unused imports in python build_system files
tp review: use anonymouse variable in for loops

use _ in for loops where the value is not used
remove pointer

NB was reporting error, removing the pointer
was: *tps.values()
now: tps.values()
examples/prediction review

mostly unused imports
review examples/bindings

unused imports, anonymouse vars
sets.Set is deprecated, use built-in set

as for python 2.6, sets.Set is replaced by builtin set()
experiments/opf reviewed

remove unused imports,
keep the NUPIC specific, even if unused (commented out code)