Update README.md
Scrutinizer code quality marker added.
InvalidArgumentException documentation
Fixes problem parsing the Windows Phone 8.1 User Agent
Update UserAgentParser.php

Added support for parsing short User Agent Strings
Formatting
Rewrite of pull request #19 to be much simpler.
empty strings -> null for more consistent handling
Tested updated
Merge branch 'toolstack-master'
Better Googlebot support added
Sort platformless to the bottom
Broad support for Crawlers added
Merge branch 'master' into os_version_detection

Conflicts:
	Source/UserAgentParser.php
	Tests/user_agents.json
Little nullable fix
Merge branch 'master' into os_version_detection

Conflicts:
	Source/UserAgentParser.php