API-wise it's odd to require absolute position with relative pointer
moves.
This cleans up some of InputRedirection code by making it simply forward
pointer input events from input devices to the pointer input device
handler, which knows better what to do with the delta value.
The pointer input device handler will compute the absolute position based
on the specified delta value, but it could also do something else, e.g.
not move the pointer at all if it's locked, etc.
Once in a while, we receive complaints from other fellow KDE developers
about the file organization of kwin. This change addresses some of those
complaints by moving all of source code in a separate directory, src/,
thus making the project structure more traditional. Things such as tests
are kept in their own toplevel directories.
This change may wreak havoc on merge requests that add new files to kwin,
but if a patch modifies an already existing file, git should be smart
enough to figure out that the file has been relocated.
We may potentially split the src/ directory further to make navigating
the source code easier, but hopefully this is good enough already.
