Add README to export ignore
Update readme and composer text
Increment version to 2.1.0
Merge branch 'extension' into release-2.1.1

Conflicts:
	composer.json
Less strict comparison for preg_match
Increase unit testing of regex
Update regex pattern
Update trim tools
Merge branch 'release-2.1.0' into test

Conflicts:
	composer.json
Merge branch 'release-2.1.1' into test

Conflicts:
	composer.json
	core/topic_preview.php
	tests/core/display_topic_preview_test.php
Stop tracking the version number in db
Set version to 2.1.1-dev