* store receiver's output into the sender's database
* rustfmt
* payment output refresh
* fix the test code in libwallet
* rustfmt
* fix wallet_command_line test
* modify the warning message for self sending
* a bit of unit test according to review comments
* display unknown value for the case of multiple outputs on single receiver, normally it's not the case of this wallet implementation
* rustfmt
* fix merge missing parts
* rustfmt
* use PaymentCommitMapping struct instead of a tuple
* rustfmt
* fix the test
* fix the owner api rpc test
* add slate upgrading/downgrading
* add slate versions
* slate versioning compilation and tests
* transaction slate responses downgrade themselves to the version of the caller
* add command line arg for target slate version output
* v2 versioning comment info
* doctest fixes
