This also moves logic for detecting which movement is associated
with given keycodes and cursors to CMovementMsg and CLinkItem,
which are better suited to contain the logic
This also fixes a bug with Page Up, Down, Home, & End not working for
the Conversation tab. Additionally, code for scrolling individual
lines in the conversation and glyphs via the arrow keys has been
removed in favor of this centrallised movement, since they were
somewhat redundant, and the mouse wheel can be used for scrolling.
This was a suggestion by dafioram; holding down Shift allows you
to skip scene transitions and edit the fragments of room glyphs.
Now with this remapping, you can alternatively just use right clicks.
