Allow list nodes to be created after clearing
Fixing up subject and type issues on empty lists

List.new previously created an empty list with subject RDF.nil and
failed to replace that subject in its graph when appending the first
items. Cleared lists that were then appended to had no type (RDF.List).
Both issues are fixed in this commit, and some tests are added forsimple
list cases (i.e. not embedded in a Resource).
Merge pull request #22 from jcoyne/after_clear

Allow list nodes to be created after clearing
Merge pull request #24 from no-reply/feature/list-type-and-subject

Fixing up subject and type issues on empty lists
preparing for 0.2.1 release
Reverting LICENSE to Apache 2

A moderate amount of Hydra contributors' code encumbers this library
with the Apache 2 license. This updates the license to reflect that,
until such time as the issue is resolved. We will work to accept only
contributions released into the public domain, and hopefully remove
dependency on non-public domain code.
Preparing 0.2.2 release
Adding some basic persistence examples to README
Require library despite gem name.
Merge pull request #30 from terrellt/feature/FixAutorequire

Named gem in gemspec appropriately.
Adding support for null relative URIs

<> must to be valid as a subject, and overrideable to support LDP.