* Move all rust crates (except lib) into crates dir, w/o nesting
* Remove stale path from .gitattributes
* Rename lib.rs files for easier navigation
* Rename mod.rs file for easier navigation
* Fix emscripten-version path
* Fix fixtures dir paths
* Use the default rustfmt settings
* Don't use nightly on CI
This patch allows users to include the parser by the same path from
local build as well as installed location. Previously it was not
possible to include the header prior to installing the built parser.
