Grid, Kernel, Framebuffer

Test of abstracting webgl stuff into 3 objects:
kernel, grid, and framebuffer

Types
Grid(width, height)
. . texture object
. . texture unit
Kernel(code, uniforms)
. . glsl program
. . uniform locations
Framebuffer(texture)
. . framebuffer

Functions
Draw (kernel, framebuffer, viewport)
. . draw to screen or grid
SetGridSubData(grid,x,y,w,h,vec4)
. . set a rectangle region of grid
SetGridPoint(grid,x,y,vec4)
. . set a single textel