Fixed StrEffect texture animation.

The result.aniframe contains a float number but it refers to the current texture index from the layer.texname array. When doing interpolation in calculateAnimation you need to increase the aniframe by to.delay * delta, so it increases slowly and when it reaches the next integer, a new texture frame will be displayed. This means that the maximum valid value for aniframe is layer.texcnt-1. 

Also the STRAnimation.delay property should not be multiplied by 1000, so I removed that.

To test the effects try: 
thunderstorm.str
jong_mini.str