dialog: Make shaders valid GLSL 1.10
dialog: Make shaders valid GLSL 1.10

The shaders before were actually GLSL 1.20, and if you don't specify a
version, 1.10 is the default according to the standard and implicit
integer casts aren't supported.

Remove the integer casts and add a version marker for 1.10 for good
measure.

jonnylamb/mx,pwithnall/mx,clutter-project/mx,jonnylamb/mx,clutter-project/mx,pwithnall/mx,pwithnall/mx,jonnylamb/mx,jonnylamb/mx,pwithnall/mx,clutter-project/mx,clutter-project/mx