Bloomchain (#1014)

* 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

ethcore/src/verification/verification.rs

@@ -228,7 +228,7 @@ mod tests {
 	use util::*;
 	use header::*;
 	use verification::*;
-	use extras::*;
+	use blockchain::extras::*;
 	use error::*;
 	use error::BlockError::*;
 	use views::*;