Properly set reply.Result to output of unmarshalled GetTxOutResult JSON.

Fix panic caused by nil pointer dereference.

Create new error type for invalid tx vout (gettxout).
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:

Add a GetDepositScript JSON result.

For now it's a stub function