Mark MCA fix as Pro only in Release notes
Bump version to 5.1.0-SNAPSHOT
Use our own Tools method to open links in external browser since the Desktop's method doesn't seem to work on Linux.
Resolve merge conflict

Merge remote-tracking branch 'origin/next' into release-5.0.0

Conflicts:
	pom.xml
	soapui-installer/pom.xml
	soapui-maven-plugin-tester/pom.xml
	soapui-maven-plugin/pom.xml
	soapui-system-test/pom.xml
	soapui/pom.xml