allow upper case NULL class constant for PSR-2
Generic LowerCaseConstantSniff and UpperCaseConstantSniff now ignore class constants
Merge branch 'master' into phpcs-fixer

Conflicts:
	CodeSniffer/Standards/Generic/Sniffs/PHP/LowerCaseConstantSniff.php
	CodeSniffer/Standards/Generic/Sniffs/PHP/UpperCaseConstantSniff.php
	package.xml
Removed MySource ChannelExceptionSniff
Added fixes for the remaining errors in this sniff