apache_request_headers need not go through recapitalization of incoming
headers and should be pass through as is.
This is a follow up on #2107 (c82b57b) by @danhunsaker;
#2409: Updated based on feedback by @narfbg;
See #2409: Remove double replacing of dashes and instead change `Content-Type` to `CONTENT_TYPE`
See #2409: Reformating and code cleanup for request_headers;
#2409: Force Content Type to go through camelization;
See #2409: Avoid overwriting global $_SERVER and set Content-Type to protected property;
Correction for issue #2388. Updated _build_message() to return a boolean. This prevents email from sending if there is an error trying to attach an attachment to the email.
Merge pull request #2409 from chernjie/develop

apache_request_headers need not go through recapitalization of incoming headers
Change boolean to bool.
Added whitespace.
Added to the changelog.
Merge pull request #2413 from buhay/develop

Correction for issue #2388.
Fix issue #2388 / PR #2413 changelog entry
Logging functions: level parameter is not optional

This parameter cannot be optional, as the following parameter is mandatory.

Also completed the corresponding documentation.
Fix a docblock in Loader class
Do not trigger a possible custom autoloader, as it is irrelevant here

These were the last two calls of class_exists() without the $autoloader = FALSE argument.
Adds a few new lines to note directive to fix a build error in the docs.
Removes an obstacle to building the docs.
Merge pull request #2440 from vlakoff/develop

Logging functions: level parameter is not optional
Merge pull request #2441 from vlakoff/develop-2

Fix a docblock in Loader class
Merge pull request #2442 from vlakoff/develop-3

Do not trigger a possible custom autoloader, as it is irrelevant here