Moved spec request stub into helper

Updated both PaletteSet model and controller specs to reflect this
Updated PaletteSet controller spec to just check that 'new' template
is rendered
Redesign: 'generate' creates & saves a PaletteSet

(as opposed to originally: generate calls PaletteSet.new and
displays results to user, but does not save to database --
originally planned to only save to db if user specifically
requested it)

Also added some more route/template render checks to
spec/controllers/palette_sets_controller
Refactored cuke and specs to use new JSON fixture

Major changes:
  - consolidated fixtures into spec/fixtures
  - renamed fixture to fit format: {name}_{num_posts}_posts.json
  - refactoring test for invalid hex color inputs in palette model spec
  - pulled post limit (10) out into a app-wide constant (PULL_LIMIT)
Refactored views

- Created a partial for the palette_set/new view
- Included above partial in both "new" and "index" views
- Deleted ERB for application.html and made HAML instead
Refactored Palette and PaletteSet models
Added Foundation, basic styling
Speed up PaletteSet by selecting smaller image

Instead of generating palette from original/largest image size,
choose image at width 500px or smaller
More specs for PaletteSet model
More PaletteSet model and controller specs
Stub info request in cuke
wrote new cuke scenario: nonexistent blog
wrote new cuke scenario: empty source
wrote new cuke scenario: blog w/o photo posts

- new palette_set model specs to test for 0 photo (0 palettes generated)
- new alert message assigned in palette_set controller
refactored spec/helpers

* condensed different types of requests into single methods
* updated specs to reflect changes
Refactored specs to use factories
Refactored cucumber tests

consolidated duplicated tests, reworded feature steps,
overrode fixture_path (and got rid of fixtures_path)