v4.0.0 (soon™)

[gigili]

Any changes and ideas relating to the v4 release can be discussed here

Breaking changes

• Remove deprecated functions from the Request class
• Rename function headers into header in Request class
• Method send from Response class will not return a self instance, as it should be last method called in the chain

TODO

• Improve PSR compatibility
• Improve DI
• Write new docs not just for code, but for usage as well