refactor api/pins

* use `current_member`
* use 1.9 style Hash syntax
* remove magic-number of ErrorCode
* use Member#pins association to find destroy pins
add spec for API error page
add parameter verification without verification plugin

policy:

 - use ApplicaitonController's filter to check parametrs
 - use config/routes.rb to check HTTP method
Use assets pipeline for CSS
Refactor import page
Delete if nest
Use variable
Merge pull request #141 from ykzts/css-use-assets-pipeline

Use assets pipeline for CSS
Merge pull request #140 from mzp/remove_verification_plugin

Restore API parameter check
Merge pull request #145 from ykzts/refactor-import

Refactor import page
Merge branch 'refactor_api_pins' of https://github.com/onk/fastladder into onk-refactor_api_pins

Conflicts:
	spec/controllers/api/pin_controller_spec.rb
fix typo
add spec of import#fetch, and fix bug.
Merge pull request #146 from onk/fix_typo

fix typo
Merge pull request #147 from onk/fix_import_bug

add spec of import#fetch, and fix bug.