Extensions
1. Added header of new API
2. Now the DB stores a list of all epochs
3. Logic of moving across epochs was changed: moving to oled non-exisintg epoch, i.e. which would have an epoch value lower the the most recent written one, is prohibited and the function call returns -1. This helps keeping the array of epochs in sorted way, in ascending order, without using sorting routines.
4. Test was changed accordingly to reflect the features and test them. The DB writing part is complete, the querying part is yet to be corrected though.