Remove ChangeLog from master branch

Keeping the ChangeLog in sync whith the branch containing the actual
release is a pain so the ChangeLog will only actually exist on release
branches.
README
Add PatternSynonyms test data to Extra-Source-Files
Temporarily restrict monad-journal version
Merge branch 'master' into release

Conflicts:
	ChangeLog
Bump version to 5.1.0.0