initial work towards accounts-ui on shark
{{#if}} treats empty arrays as falsey
add back npm-shrinkwrap, removed by accident
Merge remote-tracking branch 'origin/shark-domrange-accounts-ui' into shark
accounts-ui not dependent on global {{currentUser}} handler

Specifically, we don't have an API for defining global handlers right
now (the old Handlebars.registerHelper). We still need to devise
a new pattern for this but in the meanwhile, this is a step towards
getting accounts-ui to work.
enable dynamic templates

specifically, make {{> foo}} where foo is a helper returning
a template object render that template.
use new dynamic template pattern in accounts-ii
start fixing Spacebars tests
start breaking spacebars tests
accounts-ui: fix configured state for login services

(accidentally removed in previous commit when working
around {{#unless}} not working within class attributes
in template)
backcompat for Handlebars.registerHelper
oops, forgot to commit a file.
loginButtons is a template, not a helper
bring back Handlebars._escape
in shark, password fields aren't automatically preserved by id
fix html_scanner tests a little bit
remove old package dependencies of accounts-ui

… which shouldn't be necessary
remove whitespace
remove unused code in "templating" package
spacebars-tests package

for tests that use templates, which can't be included in the spacebars package for reasons having to do with package building/linking and circular dependencies