* Added PSR-7 Interfaces Usage guide using Zend Diactoros

* Corrected errors in documentation

corrected PSR-7 methods explanations
corrected typos
removed concrete usage of diactoros
removed unnecessary text
removed zend-diactoros autoload
added assumption of $request and $response

* Update PSR7-Usage.md

* Corrected interfaces list

Fix: Return static instead of self

* localheinz/fix/return:
  Fix: Return static instead of self

corrected malformed annotation

Update RequestInterface.php

Fix typo in RequestInterface.php

Add homepage.

UploadedFileInterface phpDoc typo fixed

Correcting inaccurate documentation

Including the homepage link makes package mirrors and directories such as those generated by Satis nicer to read and more useful (providing a direct link to the project page).

Typo s/RFC3985/RFC3986/

Coding standards for UploadedFileInterface.php

Using namespaces requires php 5.3.0 or higher

Update to latest PSR-7 version

- Syncs all interface definitions with the latest revisions on
  php-fig/fig-standards.

Sync with php-fig/fig-standards#518

Bring interfaces up-to-date with php-fig/fig-standards@b740164

Remove documentation executable bits

Sync with php-fig/fig-standards#460

Sync with php-fig/fig-standards#460 and clarify that an empty path
should be returned as "/".

Document return values for non-existant headers

Added language to withPath() regarding percent encoding

Detail Host header sources

[PSR-7] Include multipart/form-data in parsed body specified behaviors

- to match language of RFC 3986

See https://github.com/php-fig/fig-standards/pull/450

- Made Host header retrieval non-optional
- Added overrides for getHeaders() and getHeaderLines() to ensure they
  always return the Host header as well.

Per RFC 3986, section 2, reserved characters must be percent encoded.
Additionally, the implementation must not double-encode.

Per the [related PR for fig-standards](php-fig/fig-standards#446), this PR
updates the `RequestInterface` to override the `getHeader()` method and indicate
that the Host header should be pulled from the composed URI if no value has been
previously set.