This changes the way zero (which is the default) is interpreted for both
the width and height of `floating_maximum_size`. It now refers to the
width and height of the entire output layout, which matches i3's
behavior.
This also removes duplicated code to calculate the floating constraints
in three files. Before this, `container_init_floating` used two-thirds
of the workspace width/height as the max and the entire workspace
width/height was used everywhere else. Now, all callers use a single
function `floating_calculate_constraints`.
All seat operations except "down" eat the button pressed event and don't send
it to clients. Thus, when ending such seat operations we shouldn't send the
button released event.
This commit moves the logic used to send pressed/released into the "down"
operation.
This splits each seat operation (drag/move tiling/floating etc) into a
separate file and introduces a struct sway_seatop_impl to abstract the
operation.
The move_tiling_threshold operation has been merged into move_tiling.
The main logic for each operation is untouched aside from variable
renames.
The following previously-static functions have been made public:
* node_at_coords
* container_raise_floating
* render_rect
* premultiply_alpha
* scale_box
