Shortened form buttons

On small devices the form buttons got in each others way. Shortened the
button text to "Save" instead of "Save note" or "Save project". Did the
same thing with delete and other button text.
Minor comment change
Implemented current_user.box

Reusable memo call box which we will store files temporarily until they
are assigned to a Note or Transaction. We implemented tire callbacks
directly in memo and override the callback in Box so a box object is not
saved in elasticsearch.
Multiple file uploads via box to note

Use jquery-file-uploads to attach documents to holding box. When
submitting a note, the documents are attached to the note and the box is
deleted.

Implemented jquery-file-upload modal to submit multiple files at once.
Scope box docs by related id

Notes are assigned using the current document. If you are on a person,
company or project, you submit a note with that scope. Likewise we are
tagging all docs saved to the user.box with the current id.

This allows us to limit showing these documents to only the page the
documents were actually attached. When a note is submitted, the
documents are identified by the submitting parent's id, copied from the
box, and removed.
Thumbnail uploaded images

Create thumbnails of uploaded images. Save mimetype of attachments. Use
thumbnails of images or placeholder thumbnail for everything else.
Set up Amazon S3 storage for attachments

Note that we need cloud storage to be private. Amazon S3 has an
excellent expiring URL scheme which limits exposure to the public
internet.
Moved carrierwave upload cache to tmp/uploads
Forward doc#show to attachment URL

Links to files are temporary. With Amazon S3 the link is only valid for
10 minutes. If a user shows a page with files on it, leaves it open for
20 minutes, then clicks the link -- it will fail. Users leave pages open
all the time and they expect the links to stay valid.

This change links the files to their doc#show route. From there we
create a temporary URL for the doc.attachment and redirect the user to
the temporary URL. This forces creation of the temporary URL to the
moment it is required.
Attachment UI improvements

It's still rough. The UI opens the modal and shows attachments being
added. Removing attachments also work. The doc_button is updated with
the total number of attachments.
Last commit with attachment upload modal
In place attachments on note

Drag and drop attachments on a note. Doesn't work with mobile, yet.
Memos#index failing.
Various updates to doc model

Renamed doc.attached_filename to just doc.filename
Added doc.filesize as cache of attached file, well, size
Fixed current_user.box only showing related docs
Update CHANGELOG and VERSION to 0.4.1
Note attachments