Added a recipe about handling enter, leave, and motion events
on an actor.
Gives some pointers to data available from motion events,
explains a bit about stage-relative and actor-relative coords,
and covers how overlapping actors and reactivity of actors
can affect events occurring.
Examples include a simple scribble app showing how to integrate
pointer events into a more useful context.
Added some extra explanation, referencing the sample code, to
try to make the scrollable actor example easier to follow. Basically
demonstrates the principles described in the paragraph about
setting the y coordinate for the scrollable actor, but using actual
numbers.
The simple key press example in the cookbook used a brittle
and incorrect switch statement to test modifier values. Instead,
use logical "&" of the state with the modifiers we're interested
in to check which keys were pressed.
http://bugzilla.clutter-project.org/show_bug.cgi?id=2223
There was a note about constants for keys and
where they are defined in Clutter header files; but
the sentence about where key modifiers are defined
was outside the note. Logically, they belong
together.
In some cases, there were blocks of text which
were really asides/interrupts to the flow, but
which weren't explicitly marked as such. I fixed
them by turning them into <note> blocks.
Made usage of docbook elements consistent across
recipes; to ensure the conventions are kept by others,
added a section about how to write and style recipes.
