Copy & Paste from outside the segment

Some inconsistencies and changes:

• Problem: Windows (not with Ubuntu): Copy & Paste from content outside of the translate5-Tab: the newly copied content is not pasted.
• Solution: use the newly copied content.

(checked: Chrome, Firefox, Edge on Windows 10)

• Problem: When selecting only a part of a match, Copy & Paste will insert the complete match. (This was a feature before; but if users experience it as a bug, we change that.)
• Solution: Paste only the selected part of the match.
• Implementation: If only a part of a match is selected, the internal tags of the match will not be inserted into the target.

• Problem: With Ubuntu, selecting content in the LanguageResource-Matches is not possible at all.
• Solution: Allow selecting content in the LanguageResource-Matches for Ubuntu, too.