Proposed change to TweenAlpha

[TypoStraw]

In 3.7.0 TweenAlpha was changed so it also works with renderers.

However, the SpriteRenderer component has a color variable which can be used instead of changing the color in the material.

The changes:
- Added a SpriteRender variable after mMat called sRend.
- Added the following in the Cache() method:

1. if (mRect == null)
2. {
3.     sRend = GetComponent<SpriteRenderer>();
4.  
5.     if(sRend == null)
6.     {
7.                 // get material

- Updated the value property to include checks for sRend:

1. get
2. {
3.         if (!mCached) Cache();
4.         if (mRect != null) return mRect.alpha;
5.         if (sRend != null) return sRend.color.a; // <------
6.         return mMat.color.a;
7. }
8. set
9. {
10.         if (!mCached) Cache();
11.  
12.         if (mRect != null)
13.         {
14.                 mRect.alpha = value;
15.         }
16.     else if(sRend != null)  // <------
17.     {
18.         Color c = sRend.color;
19.         c.a = value;
20.         sRend.color = c;
21.     }
22.         else
23.         {
24.                 Color c = mMat.color;
25.                 c.a = value;
26.                 mMat.color = c;
27.         }
28. }

[ArenMook]

Seems fine to me, but I'll call it something else. I'll do similar tweaks to the TweenColor as well.