syndaemon: allow exclusion of shift as a modifier key

Firstly, thanks for your work in general -- you make pointing possible, and typing bearable. :-D

This is a wishlist item, but I think it's fairly important, and fairly simple to implement:
Add an option to disclude 'shift' from the keys considered as modifiers
or:
Disclude shift from modifiers by default when using -k or -K, and add an option to include it
or:
Allow selection of which modifier keys should be ignored

Rationale:
* Shift is used during regular typing.
* Typically other modifiers are not, unless doing meta operations on the text
* When shift-clicking in an active text area, everything from the caret to the pointer is highlighted.
  * If typing quickly, this means everything from the caret to the pointer is deleted, and replaced with the text after the click
  * this is painfully annoying, and causes lost productivity (if not lost work, though most apps have a useful undo option).
* Even if shift-clicking doesn't highlight text, the caret is moved, and typing continues in another area.
  * in this case (at least when typing quickly):
    * the misplaced text must be removed from the new caret location
    * areas around the text should be inspected for misplaced characters (there may have been more than one click moving the caret)
* Should be easy to implement -- the basic functionality is already present

..overall, this is really frustrating to have going on, particularly if you do things that may involve a lot of capital letters (coding, for example). But it is also frustrating to deal with the long pause when modifiers *aren't* ignored.

Ignoring modifier activity *except* that of shift allows the best of both worlds, at least for a frequent use-case.

Thanks for considering.