Rust-Lightning, not Rusty's Lightning!

Currently somewhere near 5% towards usable, published to see if there is any real interest from folks in either contributing to or using a lightning rust library.

The goal is to provide a full-featured but also incredibly flexible lightning implementation, allowing the user to decide how they wish to use it. With that in mind, everything should be exposed via simple, composable APIs. The user should be able to decide whether they wish to use their own threading/execution models, allowing usage inside of existing library architectures, or allow us to handle that for them. Same goes with network connections - if the user wishes to use their own networking stack, they should be able to do so! This all means that we should provide simple external interfaces which allow the user to drive all execution, while implementing sample execution drivers that create a full-featured lightning daemon by default.

For security reasons, do not add new dependencies. Really do not add new non-optional/non-test/non-library dependencies. Really really do not add dependencies with dependencies. Do convince Andrew to cut down dependency usage in rust-bitcoin.

Notes on coding style:

• Use tabs. If you want to align lines, use spaces. Any desired alignment should display fine at any tab-length display setting.

License is Apache-2.0.