Standars updated
Updated the phpcs ruleset.xml

- Added comments for each test to allow easy to read rule
- Added new standards tests
Fixed sniff names in ruleset.xml
Updated standards
Added Concatenation.php sniff spacing

Updated license link for Variables/ValidVariableNameSniff.php - old link was dead, directed to standard BSD licence link now.
Merge branch 'master' of https://github.com/opencart/opencart