Revert "added THChromKeyBlendFilter to support multi video overlay"

This reverts commit 586d2c84ff33d145a71c7e99748aaa7dc2a71169.
Revert "Revert "added THChromKeyBlendFilter to support multi video overlay""

This reverts commit 08f42176f4ff78ce90815053b0ef6e68b33e0d85.
added fully supported mutliple video blending