Fix left-side shader showing before first time-tag time.

[andy840119]

Should not show the yellow area.
.
What's should be fixed:

• write something like IHasExtraSize or IAffectRelativePosition to let KaraokeSpriteText able to adjust the position.'
• Add this property to OutlineShader only. Maybe will added in the StepShader also(for able to sum the outline)
• Not really sure is there any way to change the lyric sprite size? Or is there any way to change the draw size?

Also, should write a test scene:

• Maybe named TestSceneKaraokeSpriteTextWithTimeTags
• Show the lyric with single or multi outline.
• Able to change the clock time.
• Should prevent clear the expired transformers.
• Able to adjust the scale.

[andy840119]

Also, need to check how DrawSize calculated.
And should we able to change the ComputeScreenSpaceDrawQuad changed?

[andy840119]

Might create two interfaces:

• One is for calculating the masking position
• Another one will affect the drawable size?

[andy840119]

Maybe should write a test scene with big karaoke text for checking the outline issue.
Maybe named TestSceneKaraokeSpriteTextWithPreciseTiming?

Have default test value:

• Single word, the font size might be larger.
• Multi word(maybe can test effect Should add center time-tag inside every input time-tag in the input list. #163 also)

This test scene will for three test case:

• no shader
• outline shader(Fix left-side shader showing before first time-tag time. #157).
• shadow shader(Add delta transformer for the first and last time-tag. #164).
• maybe outline shader and shadow shader.

[andy840119]

Tested and guess this issue has been implemented.