Sanic-routing

- 45 Proper handling of multi-path definitions
- 40 New path splitter with lookahead and lookbehind support

Overhaul of dynamic path generation. Covers a wider array of edge cases including 35.

- Proper differentiation between `alpha` and `string` param types
- Adds a `slug` param type
- Deprecates `<foo:string>` in favor of `<foo:str>`
- Deprecates `<foo:number>` in favor of `<foo:float>`
- Adds a `route.uri` accessor
- Fixes 35
- Fixes 32
- Resolves 34
- Resolves 12
- Resolves 11
- Closes 28

Resolve bug with final segment being a regex

25 Resolve double colon in segment

24 Introduce `RouteGroup` and require every route definition to generate a unique `Route` instance