submitblock check, remove BLOCK_CHECK_SCRYPT_HASH setting

check for submitblock on init. if wallet has it, use it, otherwise use getblocktemplate submit. if we can't figure it out, try both. also, trying submitting blocks 5 times before failing.

check both hash_hex and scrypt_hex when confirming block creation. eliminates need for BLOCK_CHECK_SCRYPT_HASH setting.