Reject orphan transactions from sendrawtransaction.

This commit modifies the sendrawtransaction RPC to reject transactions
which are orphans.  This mirrors the behavior of the reference
implementation.
Improve error return from sendrawtransaction.

Rather than simply returning "TX rejected" to the RPC client which
submitted a sendrawtransaction that fails, include the reason the it
failed.
add peer to block and tx rejection debug messages.

ok @davecgh
Add createencryptedwallet support to btcctl.

This is a btcwallet extension and will not work when talking to btcd
or bitcoind.
Add createencryptedwallet to wallet request set.
Update for recent btcutil.Address API change.
Issue #90: Improve addblock logging by reporting every 10 seconds instead of X number of blocks

blockImporter now has these new properties:

txProcessed - number of transactions processed by the importer
lastHeight - height of the last imported block
lastBlockTime - block time of the last imported block
lastLogTime - last timestamp of when a progress message was shown

the p/progress option in addblocks now indicates how often you want the progress message to appear
Remove extraneous space and go fmt.
Correct the new addblock progress logging.

The code was not resetting the counters when logging a message, so the
stats kept increasing rather than showing the number of items processed
since the last log message.

This has been resolved by copying the log function directly from btcd and
modifying it slightly to work with the importer.
Expand btcctl RPC cert path to from config file.

This commit allows paths in the btcctl config file to use environment
variables and ~ as a shortcut for the home directory.

Closes #113.