Fixes #44 (hopefully!)

Fixes #43

Refers to #5

They were accidentially removed in commit cf183560 believing they had been
correctly moved by Visual Studio when refactoring the code and just forgotten
in the directory hierarchy. Who could guess Windows is so ignorant when
resolving paths?

See https://stackoverflow.com/a/10334095/2018314 for details on sharing
resources among multiple projects in a solution.

With this commit all required changes for having the configuration in
two separate files should be completed.

Fixes #18

Refers to #2

Refers to #2

We can just derive a status change from the fact that the file system
watcher has fired, so no need to evaluate all kinds of things first.

Refers to #23

Refers to #2

Refers to #2

Refers to #2

Refers to #23

Refers to #2

Refers to #2

Sometimes the TaskDialog doesn't work but raises an exception. Until we
can reproduce and fix this issue we simply provide a fallback using the
(less user-friendly) MessageBox.

Refers to #2

This is the last missing strict requirement for the first version of a
tray app, so this commit closes #2.

Refers to #2

Let the user pick a directory, check size and let the user confirm and
eventually submit it into the incoming directory after some sanity
checks.

Refers to #2

Refers to #2

Refers to #2

Refers to #2

Refers to #2

Refers to #2, #3

Refers to #2

Refers to #2

Refers to #2, #26

NOTE: currently any update to the progress bar will also re-display the
balloon tooltip. These two things should be separated!

Refers to #2