Add Lava SVG (issue #32)
Remove all occurences of TYPE_MASSIVE, etc. Closes #42.

There are no static images displayed anymore. This is probably
wrong.
Restore static sprites on XML loading.

There are still problems with front passive sprites.
Add a warning for undefined sprite types
Fix loading/saving of (front)passive sprites.

Z order is still wrong.
Rename cSprite_Manager::Set_Pos_Z() to cSprite_Manager::Ensure_Different_Z() and explain what it does.

And make it private. This is not meant to be called from outside
the sprite manager. Also fix it to properly work with massive
types instead of general types.

Currently, this causes enemies to be given Z coordinates in the same
line as other sprites, so that e.g. flyons appear before their pipe.
Don’t give enemies Z coordinate correction.

You should not place enemies over one another, really.

Now the flyons stay in their pipes :-).
Merge branch 'remove-massivity-from-sprites' into devel
Add mruby constants for the Z start values.

This makes it easier to modify a sprite’s Z position from a script.
Add array type ARRAY_LAVA.
Add lava sprite.

Uses bonusbox graphics, currently.
Use Crabmaster’s Lava images instead of the bonus box one.
Fix Lava collision rectangle
Make Mousecopy realize Lava
Disallow creating climbable lava and such nonsense
Make lava scriptable
Merge branch 'lava' into devel. Closes #32.
Add beetle barrage to SVG drafts.

http://secretmaryo.org/phpBB3/viewtopic.php?f=10&t=3900
Add Timer#interrupt to the scripting interface to forcibly halt a timer.
Terminate timers on level finish. Fixes #40.

When the level’s MRuby_Interpreter instance gets destructed, it now
terminates and frees all the timers. Note that previously the cTimer
instances weren’t freed at all, causing them to lie around forever,
creating a memory leak if you play many levels with timers in a row.