Don' use Number.MIN_VALUE for Vec3f.MIN

From Mozilla: "The Number.MIN_VALUE property represents the smallest
positive numeric value representable in JavaScript.

The MIN_VALUE property is the number closest to 0, not the most
negative number, that JavaScript can represent.

MIN_VALUE has a value of approximately 5e-324. Values smaller than
MIN_VALUE ("underflow values") are converted to 0."

This means: x>= MIN_VALUE == x > 0 for all x

and is almost never what one wanted it to mean. Vec3f.MIN
is used exclusively for getVolume()-related things which
suports that this is indeed -MAX_VALUE that is expected.

Signed-off-by: Simon Thum <simon.thum@igd.fraunhofer.de>
Fixed calculation of bounding box for Flash backend, which affected picking
Changes to allow the multiple declarations of the same style in a volume data
Consider if a light is defined before defining the light equation
Modified the texture update field to take into account style composition
multipart fixes
multipart resetcolor function
interface for particles
very first draft of ParticleSet
Merge pull request #369 from aarbelaiz/volren-duplicate-styles

Changes to allow the multiple declarations of the same style in a volume...
Merge pull request #370 from aarbelaiz/volren-light-fix

Consider if a light is defined before defining the light equation
Merge pull request #371 from aarbelaiz/volren-texture-update-fix

Modified the texture update field to take into account style composition
Merge pull request #360 from igd-geo/fix/min

Don' use Number.MIN_VALUE for Vec3f.MIN
finished first demo version of particleSet
Merge pull request #363 from yurainr/fixFlashBB

Fixed calculation of bounding box for Flash backend
implemented fieldChange for particleSet
hierarchy fix
small fixes
Add TwoSidedMaterial support
merge #367