Related to #3157 and #3159 (same changes for addressbookpage and transactionview).
Goal: Harmonize user experience for export of addresses, transactions and backup of the wallet!

- this allows removal of several Qt headers and makes use of a
standardized function in GUIUtil
- adds selected path to the UI output
Automatic sanity-testing: PASSED, see http://jenkins.bluematt.me/pull-tester/d127964a974ad83d01e80ecd82a666b90ffb6793 for binaries and test log. This test script verifies pulls every time they are updated. It, however, dies sometimes and fails to test properly. If you are waiting on a test, please check timestamps to verify that the test.log is moving at http://jenkins.bluematt.me/pull-tester/current/ Contact BlueMatt on freenode if something looks broken.