Added CategoryErrorLevelActivationStrategy, which enables setting the
Error Level threshold per log channel.
Refactored / Renamed the CategoryErrorLevelActivationStrategy to the
more appropriate ChannelLevelActivationStrategy.
Fixed phpdoc, typo and indentation issues.
Improved the Raven handler when using a Buffer handler
s/NativeMailHandler/NativeMailerHandler
added ctags generated 'tags' files to .gitingore for
added support for Pushover API priority brought up by SteveEdson in issue #187; the priority levels can be adjusted either through the handler's constructor or setters
Update .gitignore

removing tags from .gitignore following stof suggestion
Update PushoverHandler.php

simplifying the priority level setting if condition following stof suggestion
CS fixes, refs #209
Amended PR #203 (RavenHandler batch improvements)
Filtered records based on their level
Took the record with the highest severity as the main one
add error_log handler

[error_log](http://www.php.net/manual/en/function.error-log.php) handler
to send output to webserver SAPI handler (directly or indirectly)
Add new handler to the README
Fix a few details and add docs to the ChannelLevelActivationStrategy, refs #186
Added an handler for NewRelic:
* implemented a test which verifies that the fallback handler handles records when the NewRelic PHP extension is not installes
* implemented the actual handler
updated the documentation
removed the logic for the fallback handler, its out of place, adapted the "test"
refactored the implementation of the NR handler and its test:
* the test now checks that if the extension is not loaded, an exception is thrown
* the test now mocks the new relic native functions
* moved some parameters as constants in the handler class
Allow multiple users for PushoverHandler

The construct accepts a string or an array of user ids to keep backward compatibility.

In case of an array, a message is built and send for each of the users.
removed netbeans files committed by mistake