"Paste cancelled" message is too geeky

[grofaty]

pinta-1.3-preview-20120425 on Windows XP:
1. Open text editor and mark some text and copy text to clipboard.
2. Open Pinta and execute <CTRL>+<ALT>+V or <CTRL>+<SHIFT>+V.
3. Pinta reports a warning in bold "Paste cancelled" and in normal text "The clipboard does not contain an image."

It is perfectly fine that warning is returned, but in my humble opinion "Paste cancelled" is strange error to return to average end-user. It may indicate to non-geek that user has done a cancel of paste operation (That is the first thought I was thinking about). I suggest to add more "average Joe" message like in bold "Image can't be pasted" and in normal text: "The clipboard does not contain an image to be pasted."

I suggest to add this new message for the following actions:
- <CTRL>+<ALT>+V,
- <CTRL>+<SHIFT>+V,
- <CTRL>+V (related to bug 988243).

This is bug/enhancement to make Pinta more easy to use for average user.

[Cameron White (cameronwhite91)]

Fixed: https://github.com/PintaProject/Pinta/commit/1abf5e4faae6c539a753e4c67f5d5804c5676862