Bump version numbers
Remove many items of obsolete functionality prior to v3.0.0

This removes much of the obsolete functionality from the project that will no
longer be supported in v3,x.  Also, a number of unit tests have been refactored
or moved to new fixtures.  This is because (for example) the functionality upon
the Entity type relating to event-bound collections has moved to other types.
Merge branch 'release/3.0.0'