Autoproj v2.16.0 and autobuild v1.24.0

Bugfixes:

• none

New Features:

• added Autoproj.config.load_config_once and Autoproj.config.load_config_once_with_permission. These methods are meant to be used within the initialization files to load a seed configuration file once, allowing that config to be changed (and not overriden) later. The with_permission variant will ask the user first whether the config file should be loaded at all (thanks Steffen Planthaber [email protected])
• the git importer now supports doing shallow clones. Either set Autobuild::Git.shallow to true globally, or set the shallow option per importer. This is incompatible with specifying a tag or commit, as well as with the single_branch option.
• the git importer now supports using the tree SHA instead of the commit SHA for fingerprinting. In CI, this means that a branch and its merge commit would have the same SHA, allowing to save rebuild times. Set Autobuild::Git.default_fingerprint_mode to "tree" to enable globally. The option is also available on a per-importer basis as fingerprint_mode.
• It is now possible to add a post-test coverage processing step. Pass the processing as a block to test_utility.with_coverage