Release 15

Changes

• add a new script manage_alerts.pl that lets the user enable or disable alerts for an animal
  This is especially useful in the case of animals that have stopped running for some reason.
• check if a branch is up to date before trying to run it
  This only applies if the branches_to_build setting is a keyword rather than a list of branches. It reduces the number of useless
  calls to git pull to almost zero.
• require Perl version 5.14 or later
  This should not be a problem, as it's more than 10 years old.
• add --avoid-ts-collisions command line parameter
  This is for specialized uses, and imposes a penalty of a few seconds per run. run_branches.pl already does this, so it's not required for
  normal operations.
• run TAP tests for src/interfaces subdirectories
• add amcheck and extension upgrade tests to cross version upgrade testing
• adjust to changes in postgres code, file locations, etc.
• assorted minor bug fixes and tweaks