Introduce basic skeleton for Polkadot runtime. (#32)

* Introduce basic skeleton for Polkador runtime.

* Clean up the runtime skeleton.

* Make initial runtime skeleton compile.

* Compile polkadot-runtime both for Wasm ad native, allowing for testing and direct usage.

* More fleshing out on runtime.

* Update native support.

* Fix warning.

* Update gitignore

* Update path.

* Fix path.

* Remove accidentally committed files.

* Add wasm binaries.

* Fix test.

* Native storage support API.

* Add environmental module

* Add native environment to make native source-code compatible with wasm.

Also tests.

* Finish up & polish environment stuff.

* Avoid using reentrancy issues.

* Add some docs and a test.

* Remove unneeded function.

* Documentation

* Tweak docs

* Remove TODOs.

* Balance transfers + util methods.

* Rejig tests and ensure authorities are addressed consistently.

* Add marshaller for xfer function

* Transaction dispatch test....