add LGPL license header to all source files

closes gh-243
static: update base AMIs to latest 12.04 versions
update dependencies to latest versions

For both core and optional deps in both requirements.txt and setup.py.
utils: fix doctest in print_timing

Apparently I documented print_timing too closely to the form of a
doctest to the point that the latest pyflakes now complains about it.
Updated the docstring to be doctest-compatible.
remove Python 2.5 from trove classifiers
utils: add build script for 12.04 AMIs
bump version to 0.94
exception: show full state reason in NoClusterNodesFound
docs: clean-up TODO list
add USERDATA_SCRIPTS to config template
docs: document all cluster template settings

Added a table that lists all cluster template settings, whether they're
required or optional, and a detailed description. This includes the new
userdata_scripts setting.
update Changelog for 0.94 release
bump boto to latest 2.9.8 version
image: log each step of the clean-up procedure
add --exe when running nose in starcluster.test()

It seems that easy_install and 'python setup.py install' installs all
source files as executables within the site-packages folder. This causes
nose to skip all of the tests without passing the --exe option.
README: update versions in dependency list
setup: remove old pyflakes hacks

The bug where pyflakes would report redefinition of unused import has
been fixed so removing the hack that avoided the false positive from
pyflakes.
MANIFEST.IN: add requirements.txt
Merge branch 'release-0.94' into develop