Merge lp://staging/~nikwen/ubuntu-calculator-app/delete-copy-paste-fix into lp://staging/ubuntu-calculator-app

Please don't blame me for LP: #1474072. That needs tackling though. ;)

PASSED: Continuous integration, rev:208
http://91.189.93.70:8080/job/ubuntu-calculator-app-ci/356/
Executed test runs:
    SUCCESS: http://91.189.93.70:8080/job/generic-mediumtests-utopic/3074
        deb: http://91.189.93.70:8080/job/generic-mediumtests-utopic/3074/artifact/work/output/*zip*/output.zip
    SUCCESS: http://91.189.93.70:8080/job/ubuntu-calculator-app-utopic-amd64-ci/135
    SUCCESS: http://91.189.93.70:8080/job/ubuntu-calculator-app-vivid-amd64-ci/78

Click here to trigger a rebuild:
http://91.189.93.70:8080/job/ubuntu-calculator-app-ci/356/rebuild

Great job.

I have two remarks:
1. You introduced here Paste feature. We are currently not support Pasting in InputTextField. It is readonly, so you could only copy from that. You could check it by long pressing on InputTextField, there is only option "Copy". To introduce Paste feature, we need to enable it both for Phone and for Desktop.

Please create Bug report about allow pasting into calculator. And add Ubuntu UX team. They need to decide how user should be notified if wrong data is pasted. Maybe we should just paste without parsing, and trust user (we will be validate during formula push).

2. My idea was to not introduce any more regression with physical keyboard. Could you please create autopilot tests to handle "Enter", "Backspace" and "Deleted" keys? I think you already fixed that. I don't want to break phsyical keyboard support again :-)
Maybe it will be good to merge first initial physical keyboard support:
https://code.launchpad.net/~gang65/ubuntu-calculator-app/ubuntu-calculator-app-keyboard-test
?

Please split this MR into two parts:
1. fixes the delete and backspace, proper copy
2. paste feature

Hi, I'm sorry for the late reply. Thanks a lot for reviewing this. :)

I have now split the MP as requested:

1) https://code.launchpad.net/~nikwen/ubuntu-calculator-app/delete-backspace-copy-fix/+merge/266660
2) https://code.launchpad.net/~nikwen/ubuntu-calculator-app/desktop-paste-support/+merge/266662

I'll put autopilot tests on my todo list and will propose a separate MP for that. Thank you for your MP regarding this!

Regarding paste support, I would prefer merging the current desktop-only solution for now until we have a response from the UX team. We can then enable it on mobile as well.
Here is the bug report: https://bugs.launchpad.net/ubuntu-calculator-app/+bug/1480662

Thanks for splitting this branch to two separate.

I'm closing this branch, to not confuse developers.

No problem. ;)