Add a request parser.

Summary:
Parses the get and post array's. Cleans the keys up. PHP replaces certain characters one of these being a period ".", this is silly and we want to get it back.

Ref T3432

Test Plan:
Parse both request arrays and use phabricator generally.
Start submitting forms, including nested data (cc[0]=...).
Use custom fields with a period in the key.

Reviewers: epriestley

CC: aran, Korvin

Maniphest Tasks: T3432

Differential Revision: https://secure.phabricator.com/D6277