added new functions for building gram basis (from Frank)
caching of results and new newt. polytope code
bugfix in diff and speedup in subs.
Update spot_build_gram_basis.m

Removed unused variable from RandomPrune.
fixed small bugs with empty arguments.
simple speedups.
Merge branch 'master' of github.com:mmt/spotless
Finally added end support.
added flipud and fliplr.