update wintersmith and sass dependencies

npm package issues occurred with incompatible peer dependencies.
wintersmith-node-sass had a bug breaking this library
init building branches;

* move wintersmith site skeleton into wintersmith/
* breaks mozdoc serve
Site branches are now aware of each other

* add version-browser to default template
* all branches build into build/<branch name>
fix resources not being copied
style version select; add revision history

* add octicons
* refactor some css classes
faster building
extend pattern for default options in build
fix serve
fix README commands
add "mozdoc new <folder_name>"
add --output option
add --chdir option
wintersmithPath -> mozdocPath typo
remove hard-coded paths in favour of program.chdir
fix documents not being copied
custom css + fix copying resources

* better variables names for copyResources
* add css and prototypes resourcePaths
* mozdoc resources are now put in their own folder to avoid collisions
* custom user styles can be imported by making a css/styles.[s]css file.
add js and prototypes resourcePaths
include user css as <link> instead of @import
add publish command

* pushes to repo’s gh-pages
* add gulp
* wrap build as gulp task
add registration with mozilla-docs-central