1.7.34

• added API endpoints for querying project group properties
  • see https://opengrok.docs.apiary.io/#reference/0/groups
• added debug logs (at FINEST level) to the webapp for root causing greyed out history/annotate links in the UI
• made 'H A D' link display (in directory listing and search results) consistent with the minisearch bar
  • so that if History link is greyed out, the 'H' link will not be present; similarly for Annotate and 'A'
• improved incoming changes detection for Git in the opengrok-mirror tool