Add a .gitignore file for Perl modules.
Add missing dependency on Devel::Declare::Parser

This is an undeclared dependency of Exporter::Declare -magic.
See https://github.com/exodist/Exporter-Declare/issues/5
Remove direct dependency on Devel::BeginLift.

Its used somewhere else down the Exporter::Declare chain.

Also removed it from the documentation, the user doesn't need to know
implementation details.

For #3
Create and check in a MANIFEST.

It is a generated file, but it is supposed to be generated the same
everywhere, so it should be in version control.  Now we can see it
as it changes and its a lot easier to see if something incorrect
sneaks in.

It also stops Build.PL from barking about it.