pijnu parsers are no longer singletons. This has several tasty implications:

* Now we can use them thread-safely. Before, there was one Parser instance, and it had a shared State object.
* They can also be re-entrant. Previously, even if we had cloned the one provided Parser instance, each would still share the same Pattern objects, which contain a `memo` dict indexed only by the start index of each match. That means concurrent runs of the same Pattern on different input would get their memoization all mixed up.
* We can substitute different formatting ("toolset") callbacks at runtime on a per-call basis, which means we can invert control and not have to continually chase a fluxing AST shape with outside treewalkers.

Instead of importing wikitextParser from wikitextParser, import make_parser and call that. It'll return a Parser instance. If it proves slow to reinstantiate the grammar each time, we can teach Parsers and Patterns how to clone themselves (but leave out the memoization caches).
Tolerate lack of a <toolset> section in the grammar.
Adapt Pijnu so that makeParser() will not instantiate the parser anymore; other files adapted
Improve again so that we do not need to import the generated code
Avoid crash if node content is a string
Avoid crash if node content is a string (again)
Add 2 unit tests to Pijnu, testing toolsets.

This is just a beginning. Other tests to come. The tests in /test should
be adapted and moved to /tests.

One current problem is that running `nosetests tests` from the `pijnu`
folder will create a lot grammarNameParser.py in that folder... However,
code generation should soon be optional.
Rename and correct the syntax of test_toolset.py
Add failing cases in test/; they will be reported as bugs on GitHub.
Remove extra spaces in node.leaf()
Fix setup.py with missing package_dir argument so it works under buildout.
Merge pull request #6 from lrowe/master

Merged, thanks.
Rearrange package to make it work from buildout.
Unicode input fixes.
Merge d3f86c21f99 from lrowe
Fix setup.py and add .gitignore
Switch license to LGPLv3 in agreement with Denis Derman.
Fix a few bugs.
Changed returned string from leaves to unicode, it was causing encoding issues