Add Apache mod_unique_id's identifier in WebProcessor

mod_unique_id can add a unique ID to every request and also add it to other logfiles. This makes it easy to correlate lines from different logs belonging to the same request. http://httpd.apache.org/docs/2.2/mod/mod_unique_id.html
Update WebProcessorTest.php
Update AbstractProcessingHandlerTest.php
eAccelerator doesn't like anonymous functions.

- Change to private instance method for error handler.
eAccelerator doesn't like anonymous functions.

- Change to private instance method for error handler.
Changes from comments.

- Move private instance variable.
- Reset errorMessage.
- See https://github.com/Seldaek/monolog/pull/248
Merge branch '1.6.0_with_fix_for_eaccelerator'

Conflicts:
	src/Monolog/Handler/StreamHandler.php
Add unique_id to extra data only if present in the server environment
Merge pull request #247 from mpdude/patch-1

Add Apache mod_unique_id's identifier in WebProcessor
Fixes based on comments.

- Change function to private.
- Use private variable correctly.
Merge pull request #248 from birkirb/master

eAccelerator doesn't like anonymous functions.
HipChatHandler: combine batch records and send as one
CS fix
Merge pull request #252 from astina-forks/hipchat_batch_records

HipChatHandler: combine batch records and send as one
Ignore json_encode errors
Update LineFormatter.php
Add timezone to Dates
Merge pull request #254 from kamisama/fix/cubehandler

Add timezone to CubeHandler Dates
Add logging of exception line and file path to gelf message
Merge remote-tracking branch 'tarjei/master'