Add missing rpc commands and mark as unimplemented.
Add estimatefee and estimatepriority to btcctl.
Correct comment type for newInboundPeer.
Add getmininginfo to btcctl.
Add new testnet seed testnet-seed.alexykot.me
Implement a built-in concurrent CPU miner.

This commit implements a built-in concurrent CPU miner that can be enabled
with the combination of the --generate and --miningaddr options.  The
--blockminsize, --blockmaxsize, and --blockprioritysize configuration
options wich already existed prior to this commit control the block
template generation and hence affect blocks mined via the new CPU miner.

The following is a quick overview of the changes and design:

- Starting btcd with --generate and no addresses specified via
  --miningaddr will give an error and exit immediately
- Makes use of multiple worker goroutines which independently create block
  templates, solve them, and submit the solved blocks
- The default number of worker threads are based on the number of
  processor cores in the system and can be dynamically changed at
  run-time
- There is a separate speed monitor goroutine used to collate periodic
  updates from the workers to calculate overall hashing speed
- The current mining state, number of workers, and hashes per second can
  be queried
- Updated sample-btcd.conf file has been updated to include the coin
  generation (mining) settings
- Updated doc.go for the new command line options

In addition the old --getworkkey option is now deprecated in favor of the
new --miningaddr option.  This was changed for a few reasons:

- There is no reason to have a separate list of keys for getwork and CPU
  mining
- getwork is deprecated and will be going away in the future so that means
  the --getworkkey flag will also be going away
- Having the work 'key' in the option can be confused with wanting a
  private key while --miningaddr make it a little more clear it is an
  address that is required

Closes #137.

Reviewed by @jrick.
Update mining-related RPC handlers for new code.

Now that btcd support CPU mining, update the getgenerate, setgenerate,
gethashespersec, and getmininginfo RPC handlers to return the appropriate
information.

Also, remove the various extra help addenda about btcd not supporting
mining since it is no longer true.
Fix log message.
Switch pingtime and pingwait to float64.

Needed to match bitcoin-core and btcjson.

ok @davec
Fix typo.
IMPORT PATH MODIFICATION CHANGESET
----------------------------------

Please use this changeset as the first one on top of the conformal codebase.
Note that if there are new imports, they need to be changed as part of this
changeset. In general, use "git rebase" on github.com/conformal's version
and apply this changeset first.