Re-introduce "loggerdb revamp:""

This reverts commit 9235c78e29df3c4f2716feccc257a3c8468c4a37 (so reverts
a revert with additional changes/fixes)

Conflicts:
	indicators.py
loggerdb: Cleanly handle DB structure changes
Fix DB resume scheduling issue

Issue:
As noted in the original "loggerdb revamp" commit, resuming with a
recent DB would cause an irregular delta between the last candle, and
the new candle.

Solution:
We now wait until the next candle would have been created before
starting out threading implementation.
avarice: PrettyMinutes
README: we now support resuming!