Merge pull request #230 from stepasite/master

Extrusion node fixes
fixed broken height field due to pull request #230
mpeg Dash in X3dom Movie Texture
x3dom_mpeg_dashe xample
fix
replaced function name isMoving() (viewarea) by isMovingOrAnimating(), and added corresponding getters for the two members _isMoving and _isAnimating
Fix for flipping bug of turntable mode
Update Texture.js
Update Texture.js
Merge pull request #232 from kapekost/x3dom-mpeg-dash

X3dom mpeg dash
optimized last pull request (dash)
more video instances

updated example to use 2 dash videos ( from different servers fast/slow-beta) and one mp4
multiple dash Video textures fix
Merge pull request #236 from kapekost/patch-2

multiple dash Video textures fix
Merge pull request #237 from kapekost/patch-1

more video instances
cleanup of dash stuff: load dash script only if required, not always
volume rendering changes
Added preliminary version of Projection Volume Style.
Corrected the first local maximun and minimun condition for the maximun and minimun projection styles
Make some changes and modified the currently implemented styles accordingly
  * Use of inheritance to not repeat the common shader text in all the styles
  * Modified the volume rendering integral (the way the color is accumalated)
  * Added a global light equation without considering materials
  * Added a function to get normals from texture when provided or calculated from central differences if not.