Add MaxTime field support from BIP0023 mutations.
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