Double is used here.
Rename simplified fluid level flag.
Can't stand on a minecart, give little more room for boat.
Switch 1.4.x snow level handling to an extra flag.
[BLIND] Implement MC 1.5 snow levels with an extra block-flag.
Can't stand on minecarts in 1.4.7 either.

(Skipping older versions.)
Override cleanup methods in BlockCache implementations to remove world
references.
Can still not stand on Minecarts (dev branch).
Remove the old snow-level flag for leveled snow.
Move utility methods for altering flags to the BlockFlags utility class.
Set version to 3.8.11-RC for release on BukkitDev.
Fix PassablRayTracing not respecting block flags.

Heavier but more consistent: use BlockProperties.collidesBlock, since we
don't really check the blocks bounding box against a ray anyway, but
collision with the full moves bounding box. Getting a blocks shape
should some day be routed through BlockProperties so the shape is
correct from the start.
Add example entry for overrideflags (snow: default).
Set version to 3.8.12 for further development.
New FastClick (inventory) check.

This check is less strict on short term but more strict on medium term.
Keeps track of one second (200 ms resolution).
Ignore "outside" clicks, i.e. slots outside of the inventory slot range.
Inventory.FastClick: Fix vl not adding, prepare for 1.5.
Set version to 3.8.12-RC for release on BukkitDev.
Also catch getSlot() < 0 for the InventoryClickEvent.
Set version to 3.8.12-RC2 to distinguish quick fix release.