Implementation of the alt and copyright fields in image views, that are returned by the JSON
SearchForm now accepts Ref instance in addition to refs string
SearchForm: Add exceptions for 401 and 403 responses
SearchForm#set now accepts field_name whose doesn't exist in form
SearchForm: Actually use provided default values
Merge branch 'feature/search-form'
Json parser: Clean code
Add some doc
fix: Prismic.api now actually pass the access_token
Fix HTTPS calls

This commit fixes HTTPS calls by setting the use_ssl options.
Allow to specify a custom HTTP client
Merge branch 'feature/http'
Fix DefaultHTTPClient's multi-values with Ruby 1.9.2

Ruby 1.9.2's URI.www_encode_form does not support multi-values parameters.
Image: Don't need to add optional parameters

Fragments can only be created by the JsonParser, there is no need to
optional parameters. Keeping them could lead to confusion.
Image: Always define “alt” attribute

The <img /> tag should _always_ define an “alt” attribute, and there is
no reason for @alt to be nil, so we can always use it (in the worst
case, it will be empty).
Merge branch 'alt_copyright_in_image_views'
Bump to 1.0.0.preview.6
Update the Ruby kit documentation