Subtle changes, bugs and feedback

Subtle changes for today:

• Search messages
  
• Search single message
  
• Removed "Got something to add?" above action buttons
  
• Removed extra pixel from search form
  
• Renamed "Start a conversation" to "Post conversation"
  
• Renamed "Start an event" to "Post event"
  
• Tidied up a small part of pagination in order to re-assess how it should look on mobile in readiness of header navigation being repeated in the footer