use compressed public keys by default

NOTE: The KeyGenerator will now use different addresses than before!
simple utxo-based storage backend, fix dummy backend
utxo cache, fixes, cleanup
utxo store: cache deleted utxos, implement reorg, cleanup namecoin support
fix some wallet issues to work with utxo store
cleanup storage initialization
enable utxo_cache by default, disable utxo_cache and increase intervals when synced
don't create logger if dir doesn't exist
remove unneeded db query left over from debugging
utxo store optimization
cleanup sql schemas, use Sequel::Migrator, store and check backend and network magic
move namecoin-specific storage features into Namecoin module
don't let txouts that are spent in the same block touch the DB at all
rescan / watch addresses
wallet: register new addresses with storage and provide rescan option
fix node option parsing
rebase to master
skip schema creation if db seems to already exist
tx forwarder example demonstrating the "monitor output" and "create/assemble tx" API