iUniform usage improvements

[theetcher]

Let me suggest following improvements:

• Update iUniform value of vector attributes during slider drag. Currently it will update only when you release the slider, Usual single float uniform updates correctly, vector only after release.
• Change non-slider iUniform values using mouse wheel. Focus on the field with mouse and:
  * Usual scroll - changes with user defined
  * Shift + wheel updates with (10 * step)
  * Ctrl + wheel updates with (0.1 * step)
• If iUniform will be controlled by mouse wheel it will be handy to have vector uniform as a row of N values like that:
  

Thank you for what are you doing, This extension is really awesome.