use InstancePool for PHP-side object caching
more convenience methods
updated diagram
add index to column typeID on table invTypeReactions, as it is frequently hit during Type subclass decision
extract commonality from classes into SdeTypeCommon and refactor their instantiation API to be more consistent
adapt README and diagram to recent refactorings, + some minor bits
fix to skill level sanity check
refactored blueprint activity methods to extract commonality into addActivityMaterials()
Merge branch 'dev'