* added simple procedural texture for vectors with rounded line ends and beam smoothness
* added optional -vector_beam_smooth option
* removed -antialias option, antialiasing is now always applied, except for plain D3D
- vector_length_ratio is now independent from screen size
- changed vector_length_ratio range from [0.0, 1000.0] to [0.0, 1.0]
- updated display name and description of vector_length_scale vector_length_ratio
- removed POT texture size from shadow mask in HLSL, U/V size is now simply the percentage of the actual texture size
- adjusted display names of options
- separated curvature parameter into distortion, cubic_distortion and distort_corner
- distortion and cubic_distortion can be negative, to compensate each other
- distort_corner is intependent from the image distortion
