High Memory usage

Calculating c_l^m data for large images with a large l will cause huge amounts of memory to be used due to the precalculation of all P_l^m. There should probably be  a way to tell the the library how much memory its allowed to use to prevent swapping. Which slows the whole algorithm to a crawl.

Example: l = 2500, image: 12572x6286 px -> ~80GB memory