Read S3 options

Read the file_strage and s3_credentials options
Add default storage settings for file, example s3
Don't use a proc to get the s3 settings
Merge branch 'master' of https://github.com/danielwestendorf/rich into S3
fix error in file storage type and make it the default for backwards compatibility
Update README.rdoc

add note about S3 compatibility
Merge branch 'master' of https://github.com/danielwestendorf/rich into DA
add default values, default placeholder image to inline 1px transparent pixel
refactor preview_width to preview_size which will be used for max width and height (its the bounding box)
preview size, hidden input and object link support for Rails Admin
ignore rvmrc
formtastic rich picker uses rich files when the rich_picker field is an integer

Issues:
- does the javascript understand this and place the ID in there?
- why is the label not showing up?!
- need the asset path for document-thumb or css
get thumb path to image object directly from Paperclip
typo in preview_size
clean up the formtastic picker input, add labels

(and some changes to the dummy app to quickly test without AA using a simple formtastic form)
revert to Paperclips built-in S3 support
default to a 100px bounding box for image previews
do not show style selector when linking an object
do not update the image preview for 'file' type uploads
formtastic: do not show the image preview for file type pickers