Change standard Insert Tag keyboard shortcut

[cburatto]

The default shortcut to insert a source tag into target is CTRL+Right Arrow. But this shortcut is used intensively while editing to jump word-by-word to the right. Although you can change the shortcut on the Tools > Options menu, it would be nice to have another default shortcut instead of CTRL+Right.

Example:
To "cycle-through" the source tags, ues CTRL+ALT+RIGHT or LEFT.
To copy the current highlighted source tag, use CTRL+ALT+DOWN