Add a field in the Config for dist_transforms.
Allow the default config to be changed.

Also accessed as a class method without needing the HasConfig role.
Only building the authors should greatly speed up index creation.

authors are only about half the lines in the index.
Install a patched version of BackPAN::Index on Travis.

This is necessary to get the normalization code, it hasn't been
merged or released yet.
Change the Gitpan::Config backpan transform options to match how BackPAN::Index works

Also add an option to make BackPAN::Index always update regardless of cache time.
Attach BackPAN::Index to the new backpan config options.

Be careful not to override any defaults if the config is empty.
Add BackPAN normalization and new config options.

In production, we always want to update the BackPAN index at startup and
not wait for the cache to clear, because we don't know the BackPAN mirror
update cycle.  But we don't want that in testing.
Test BackPAN normalization.
Merge branch 'issue/68' into rewrite