Adopt a development/release procedure in Drush make files

I am going to start adopting a new procedure in the Drush make file that I think will help with both development and tagging releases.

Summary of release tagging procedure:

(Each will be a separate commit.)

1. Update the version number on all farm projects in make files.
2. Uncomment the line with the official version number. Comment the lines for the Git development branch. Tag the release.
3. Revert commit #2 to continue the development branch.

See more details below...

In build-farm.make:

During development, the build-farm.make file will be set up to checkout the latest commit of the 7.x-1.x branch of the Git repository. But it will also contain the current stable release in a commented-out line above that):

projects[farm][type] = profile
;projects[farm][version] = 1.0-beta8
projects[farm][download][type] = git
projects[farm][download][url] = http://github.com/farmOS/farm.git
projects[farm][download][branch] = 7.x-1.x

When it's time to tag a new stable release of the distro, I will update the version number, uncomment that line, and comment out the Git lines (2 separate commits so that the second one can be reverted as a followo-up:

projects[farm][type] = profile
projects[farm][version] = 1.0-beta9
;projects[farm][download][type] = git
;projects[farm][download][url] = http://github.com/farmOS/farm.git
;projects[farm][download][branch] = 7.x-1.x

This was already being done, for the most part, but I was replacing the lines each time, rather than just commenting them out. For example, here is the commit for the 7.x-1.0-beta8 release:

http://cgit.drupalcode.org/farm/commit/?id=d66f6a0d59c86ec8ac7c798690fdf...

And here is the commit right after:

http://cgit.drupalcode.org/farm/commit/?id=6ac490cac2ed4d6d0e1032cb6a125...

In drupal-org.make:

The same as above will be done for all farm_* modules.

After the release is tagged, I will revert the commit that swaps the commented lines, so that we can resume development using the latest commits of each project.

I hope that this will streamline some of the development process moving forward.