Work In Progress - Composer & PSR-0 compatibility

This Work In Progress pull request is used to discuss the implementation of PSR-0 and compatibility with Composer.

- [x] Create PSR-0 folder structure
- [ ] Rename all `class.`-files
- [ ] Decide on what namespaces to use
- [ ] Implement namespaces
- [ ] Update class references in code
- [ ] Add [ValidForm Builder 3](https://github.com/neverwoods/validformbuilder) as a composer dependency
- [ ] Update PunchCMS Form Builder to be [ValidForm Builder 3](https://github.com/neverwoods/validformbuilder) compatible
- [ ] Update PunchCMS Wizard Builder to be [ValidForm Builder 3](https://github.com/neverwoods/validformbuilder) compatible
- [ ] Add [Bili](https://github.com/neverwoods/bili) as a composer dependency

*Add anything that's missing in this list*