Remove vars from the babushka DSL. (deprecated on 2012-06-12).
Don't load or save vars anymore.
Clean up ~/.babushka/vars when babushka is run (to revert after around 2012-08).
Remove the logic from Babushka::Vars, converting it to a module for the #removed! calls.
There's no such thing as a dynamic value when prompting anymore.
Remove vars from bug reports.
Remove the var load and save logic from Babushka::Task.
Rename vars to args as appropriate.
Prompt has never responded to :var -- this is a refactoring relic.
Reword some --help descriptions.
No need to include source_support in task_spec.
Remove Hash#reject_r[!].
Add some parens in Babushka::Task.
v0.15.8 - Improved python/pip handling, 'src' template and 'build tools' updates.

* Improved python/pip sudo handling -- thanks to @tamird
* Updated python/pip deps to install headers on all platforms
* More consistent 'build tools' behaviour with simplified deps
* Avoid unncessecary 'build tools' installs from 'src' deps
Merge branch 'remove-vars'. Onwards and upwards!
Merge branch 'cleanup' -- some things I found while removing vars.
Remove the deprecated :branch 'babushka babushka' param.

Better to just remove this one instead of using #removed!,
as that would make it explode, which isn't normal behaviour
for an unexpected dep argument.
Remove deprecated .managed, .src, and 'sudo' deps.
Merge branch 'deprecations'
v0.16.0 - No more vars! Inching towards v1.0.