Added Plugin namespace for plugin/coreblocks/block.search_form
Do not create link when website is empty for recent comments box

Add class such that themes can use `#recent_comments .username` for styling
names and make the "user [commented] on post" string translatable.
Merge pull request #45 from Lekensteyn/fix-comments-menublock

Do not create link when website is empty for recent comments box
Merge pull request #44 from Lekensteyn/fix-namespace

Added Plugin namespace for plugin/coreblocks/block.search_form