Gotchas and peformance to address

[Stefan Bringuier]

• The oliynyk database has Missing data types, add option in readdatabasefile function to fill with some value (default 0.0 but probably want average for database.
• Add multithreading to assignfeatures loop.
• Remove as many Abstract data types. This seems to be causing large memory allocations in first call.
• Fix range call in removeunsupported!
• combinefeatures is not implemented correctly for various scenarios.
• Work in support for custom element data sets. Requires working back through generatefeatures-> processinputdata -> ...