Addressbook

Fixes #351

This PR add support for create/delete labels for addresses on Send page.

* Mocha tests for create, get and delete.
* Modal popup to input the label and address.
* Create/Delete an object of label/addresses and store in LocalStorage. (One label to one address is allowed)
* Click on "label" to paste address on input field Address.
* Show list of label with its address on SendPage.
* Send and synchronise address book with All copayers.
* Karma test for SendController.

Note:
* Delete action does not "delete" element of the object. Just put '-1' to copayerId and update "createdTs".
* The key of the object is the address.

In the future (new issue or something):

* We could add a signature for each entry. (signed with the public key of copayer who created the label).