1.0.0: SQL table `contract` change + SQL type change for mezos + more and better logs + misc

todo

• put back block hash (short version) next to block level, otherwise can't distinguish uncle blocks
• add more logs

version bump to 1.0.0

This version number (1.0.0) follows the new rules explicated in #21 (closed)

There's indeed a breaking change regarding the database. Two columns in table contract have become nullable. If you run this version on an existing DB, it'll crash when it tries to insert null values in those newly nullable columns. If you do not want to re-run the indexer from the beginning, you may just alter the 2 columns to make them nullable. But some old values in those columns will be wrong.