Update token enum capitalization for latest rust
Change fail! to panic!
Remove implemented features from DESIGN
Rename a variable
Rename generate::World to Entities
Refactor
Move intermediate output into dedicated module
Move final output code into dedicated module
Created type alias for item vector
Rename Entities to EntitiesGenerator
Rename Entity to EntityGenerator
Add support for events syntax

This has no other effect besides parsing the syntax without an error.
This is a preliminary step towards support for systems.
Add support for system declaration syntax

This doesn't have any effect yet besides parsing the syntax. It is a
preliminary step towards support for systems.
Start adding support for systems

Please note that, although they are part of the API, Systems has no
notion of events yet. On calling trigger, all known systems will be
called.
Refactor
Only trigger system on its event
Group related type definitions
Upgrade to latest Rust nightly
Remove Clone requirement from Control

Before, Entities used with Control needed to implement Clone.
Remove most trait requirements on components

Components still need to implement PartialEq and Show. I can't easily
remove those, since the unit tests depend on them.