bake: Make pipeline processing multi-process. Not many changes here, as it's pretty straightforward, but an API change for processors so they know if they're being initialized/disposed from the main process or from one of the workers. This makes it possible to do global stuff that has side-effects (e.g. create a directory) vs. doing in-memory stuff.

colorama==0.3.3
compressinja==0.0.2
Jinja2==2.7.3
Markdown==2.6.2
MarkupSafe==0.23
Pygments==2.0.2
pystache==0.5.4
python-dateutil==2.4.2
PyYAML==3.11
repoze.lru==0.6
smartypants==1.8.6
strict-rfc3339==0.5
textile==2.2.2
Werkzeug==0.10.4