Merge pull request #209 from mattyb149/master

Clean up marketplace.xml to pass schema validation
Changed location for the 5.0 language pack installers
 'New version of plugin metadata'
Update marketplace.xml

Update the max_parent_version for Startup Rule Engine market entry in marketplace.xml to 5.2.99.
Merge pull request #210 from vitordeatorreao/patch-1

Update marketplace.xml
 'New version of plugin metadata'
Added version 2.1.0 of Avro Output Plugin
Merge pull request #212 from cdeptula/master

Added version 2.1.0 of Avro Output Plugin