goimports -w .
Throttle RPC and WS concurrent active clients

This change set implements tunable concurrent active clients throttling.
Mark imported script addresses for their account.

Spotted by @tuxcanfly.
Test active addresses including script addrs.
Write imported multisig addresses to disk.

When the addmultisigaddress RPC was called, the wallet with the
imported address was not being written to disk, and if no more writes
were scheduled, the address could be lost.  This change immediately
writes the updated keystore to disk before the RPC returns.

Closes #98.
Move last seen block to RPC client structure.

Pass the RPC client to the notification handlers.  Update the last
seen block for blockconnected notifications in the client structure
directly, protecting access with a mutex.
IMPORT PATH MODIFICATION CHANGESET
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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.
Task #396 on Task Board:

Create a stub websocket call getdepositscript.