Make our code DRY by consolidating use of strtoupper

HTTP request methods are always uppercase
Ensure `-` == `_` in header names
Parse JSON parameters from the request

Adds JSON parameters to the request data, but parses them as late as
possible to avoid performance issues.
Use offsetExists for checking parameter existence
Fix error checking logic
Make canonicalize_header_name public and static

This doesn't rely on request state, plus it's easier to test this way.
Add tests for the request object
Add method to get JSON parameters
Repeating Docs in class-wp-json-meta.php

Two docs repeat about a line apart, just making it one :)
Merge pull request #630 from NikV/patch-1

Repeating Docs in class-wp-json-meta.php
Merge pull request #626 from WP-API/two-parse-json-data

Parse JSON data from the request
Remove old taxonomies controller

It has been replaced
Speed up builds by only running against MS once
Merge pull request #637 from WP-API/rm-old-tax-terms

Remove old taxonomies controller
Merge branch 'develop' into strtoupper-method

Conflicts:
	lib/class-wp-json-server.php
Merge pull request #589 from WP-API/strtoupper-method

Make our code DRY by consolidating use of strtoupper
Move WP_Test_JSON_Testcase to a properly named file
Also move SPY JSON Server class
Run 5.2, 5.3, and 5.5 against single site, and 5.4 against multisite
Merge pull request #643 from WP-API/mv-json-testcase

Move WP_Test_JSON_Testcase to a properly named file