General cleanup of some of the code
Removal of EntityIndex and EventIndex classes and using mango equivalents with the same name
Additional cleanup
More cleanup.  Using constants more consistently across the codebase. Optimized imports
Rename of delim constants to more specific NULL_BYTE, ONE_BYTE, and END_BYTE
Merge pull request #180 from calrissian/prerelCleanup

Prerel cleanup
Small bug fixes.
Fixes #187
Fixes #186
Fixes #184
Fixes #183
Allowing metrics store to perform queries either missing types OR missing groups (the store will query the best index in both situations). One of these MUST still be supplied, however.