ignore vim's .swp by default
mv assets.py to assets/__init__.py
new signature for engine.fromfile
integrate webassets into Acrylamid
document webassets integration
Merge branch 'feature/webassets'

Currently only working for Python 2.6 and 2.7 (Webassets is not yet compatible
with Python 3 but they are working on this) and Jinja2. Merged to escape a
possible refactor hell later.
fix TypeError in new template signature
entry.path returns path without content_dir and extension (useful for /:path.html)
remove themes and init from core
remove check, deploy and pingback task
task discovery in tasks/ directory
update commands docs to reflect recent changes
refactor pagination code into Paginator mixin