guard+spring+rspec+cucumber setup,
removed ActiveRecord tests from project,
closes #1084,#1088,#1089
removed cucumber from project, decided to use rspec request tests as capybara features
rewritten cucumber feature as capybara feature spec
added gadget model
bootstrap-optimized error fields rendering instead of scaffold defaults,
bs_alert helper for bootstrap dismissible alerts for flash messages
added feature specs for empty gadgets list, new gadgets creation
create gadgets, list existing gadgets, show gadget
closes #1093 @0h10m #1094 @0h10m #1095 @0h10m
moved create new gadget test to shared example "visually creatable" to keep spec DRY
TDD: added requirement to display only gadgets of current user
gadgets belong to users, user has many gadgets. Updated model specs and factory
only gadgets of current logged in user are listed on gadgets page
added different gadget view modes changing with ajax without whole page reload
added overlay and loading spinner on ajax request
refactored view_modes_selector partial, added gadgets helper