v0.17.0 - Better platform detection; many fixes & cleanups, see below.

Rework the SystemProfile layout for better platform handling; see d6ac679.

Properly parse `gem env` output as YAML in GemHelper and remove some deprecated methods.
Remove unused options from DepTemplate and deprecate them in the DSL.
Remove unused Array#to_list options.
Refactor & spec BrewHelper installed package querying.
Expose log opening, so logs can be re-opened at runtime; thanks to Richo Healey.
Use git plumbing instead of porcelain in GitRepo where appropriate; thanks to Richo Healey.
Add new release names for Ubuntu, OS X, etc.
Add GitRepo#resolve_full alongside #resolve.
Migrate internal contstants to CONST_CASE with deprecations.
Fix `babushka edit` when EDITOR, etc not set; thanks to Justin Wark.
Tighten the Dep('name') DSL method.
Remove `babushka search` stub after removing the command itself.
Fix acceptance specs, and the main specs on travis.
Spec logging cleanups.
Bundle update & related rspec deprecation updates.
Removed a lot of info from the README that was out of date or duplicated the docs.
Correct some license references in the README (no license changes, though).