* The APKINDEX parser used to return a dictionary with one package for
a given package name. This works for the installed packages database,
because there can only be one provider for a package. But when
parsing packages from binary repositories, we need to support
multiple providers for one package. It is now possible to get a
dictionary with either multiple providers, or just a single provider
for each package.
* Dependency parsing logic has been adjusted, to support multiple
providers. For multiple providers, the one with the same package
name as the package we are looking up is prefered. If there is none
(eg. "so:libEGL.so.1" is provided by "mesa-egl"), it prefers packages
that will be installed anyway, and after that packages that are
already installed. When all else fails, it just picks the first one
and prints a note in the "pmbootstrap log".
* Added testcases for all functions in pmb.parse.apkindex and
pmb.parse.depends
* pmbootstrap chroot has a new "--add" parameter to specify packages
that pmbootstrap should build if neccessary, and install in the
chroot. This can be used to quickly test the depencency resolution
of pmbootstrap without doing a full "pmbootstrap install".
Fixes#1122.