qt: rework "receive coins" workflow
qt: remove verify/send message and send coins from address book

These no longer make sense in the new workflow. It's less
clicks to reach sign/verify message from the menu. And sending
from the address book is one kind of automatic address reuse
we're trying to avoid.
qt: allow dragging, copying and saving QR code

Add context menu and drag handling to QR code widget.
qt: add message field to SendCoinsRecipient

Also update URI parsing to fill in this field.
Note that the message is not currently used in any way with the client.
It should be stored with the transaction.
qt: use SendCoinsRecipient for payment request information

This brings some symmetry into the design by using the same object
both for incoming URIs that are parsed as for outgoing URIs that
are formatted.
qt: move bitcoin URI formatting to guiutil

Follow the same pattern as the parseBitcoinURI function.
qt: show payment information in one text area

Simplifies the dialog (makes it look less crowded) as well
as the code and makes it possible to copy multiple fields at once.
Also format bitcoin URI as URI, add copy button for URI.
qt: general polish after adding new receive flow

- We no longer have an address book, but "address lists", update message
  accordingly
- Add tooltips here and there
- Clarify text on buttons
- add Copy Address button to receive request dialog
Merge pull request #3099 from laanwj/2013_10_new_receive_flow

qt: improve "receive coins" workflow