added some docs about osm log mechanism
housekeeping: routine imports organization
Housekeeping: eliminate compile warnings, dead code, etc.

This reduces the number of compile time warnings (as
reported by eclipse) from 257 to 83. Some about using
deprecated APIs are left for a next round.
fixed typo
Housekeeping: add missing (c) headers
Reimplement MongoGraphDatabase without blueprints
Remove blueprints dependencies