* use bloomchain crate in blockchain module. remove obsole chainfilter submodule

* update database version to 6.0

* removed redundant line

* simple db migration

* make migration slightly more functional

* bloomchain migration

* migration version is just a single unsigned integer

* updated migration v6

* parity migration

* db migration

* removed hardcoded migration dir

* replace ptr::copy with clone_from_slice, removed potential endianess problem from trace/db.rs

* removed superfluous line

* blockchains log blooms config is not exposed any more