Also added some minor clarifications on the setup and verification of `x*G` on other chain, as well as a more detailed section on how this would work on bitcoin.
* Beginning to remove in-process miner
* rustfmt
* rustfmt
* rustfmt
* rustfmt
* remove pow crate and put remnants into core
* rustfmt
* fix test compilation in core and chain
* rustfmt
* Updating server tests to use test miner
* rustfmt
* rustfmt
* remove pow from test matrix
* adding basic stratum stats to TUI
* run stratum server at all times, and halt messages while syncing
* fix core tests
* add ability to run internal test miner for cuckoo 16 testing
* modify build instructions
* Bump up crates versions
* Finally add a Cargo.lock to avoid dependency breakages
* Build doc update for testnet2
* Fix test framework not really using its mining config
* Testnet2 genesis, best so far at 128 difficulty (a nice number)
* Minor build doc update
* move FAQ.md to https://github.com/mimblewimble/docs/wiki/FAQ and unduplicate (Troubleshooting segment already present on its own wiki page)
* Update doc/style and move it into CONTRIBUTING.
* group up docs overview for more clarity
* link to previously unlinked content in the docs overview
* update + cleanup doc/build
* Update links to reflect troubleshooting is now only in the wiki
* More link fixes and spelling
* Remove doc/usage.md that I've faile to keep updated, and use a wiki page instead
* Last forgotten CONTRIBUTING.md fix
* remove difficulty field from block_header (derive from total_difficulty)
* address feedback on PR and general cleanup
* rustfmt
* rework pow/difficulty validation in pipe::validate_header
now that we only have total_difficulty available
* cleanup various todos
* rustfmt
* rework DifficultyIterator to track header and prev_header state
* rustfmt caught some garbage syntax
* cleanup
