add canvas cursor blink

[Abdillah]

Hello,

I add basic cursor blink feature. Actually, I observe that other editors seem to have different fade and opaque interval. If this change is fine, I'll continue.

[Abdillah]

Oh no, I figured out that the timeouts messing even after the cursor been moved, therefore creating unexpected glitch here and there after.

Then, your solution still hold. I will try to implement one of them.

[Abdillah]

To avoid too much refactoring for my first try, I resort to my previous way by fixing the glitches (some glitch still happened but more acceptable).