* update mean cuda miner to latest trompcode, and added tweakable parameters to grin configuration file
* Added UUID for transactions, and store aggsig contexts indexed by transaction ID
* updating test framework to allow checking of wallet contents during test
* allow selecting a commit while providing a key index
* added static reference to libsecp that can be called throughout
* don't serialise rangeproof to json if it's not desired
* store wallet output data in hashmap
* cleanup up commented out code
* pass pubkey/identifier and not derivation around to miner etc.
* fix failing tests
* introduce grin_keychain, encapsulate derivation of secret_keys
* core compiles against keychain, tests don't run yet
* core tests are now passing against keychain
* wip - getting wallet working with keychain
* add util and keychain to travis test matrix
* basic test around key derivation