Fix npatch visual auxiliary bug

Bug 1 : If auxiliary image and npatch image has alpha,
The final scene doesn't have alpha color.
It cause mask npatch shader don't consider alpha value.

Bug 2 : LoadPixelBuffer reload policy is FORCE in default.
And we load auxiliary image as LoadPixelBuffer.
So, sometimes auxiliary load canceled due to the force reload.
+ auxiliary didnt cached.
We make Auxiliary load as TextureManager so the lifecycle
works well.

Change-Id: I4ed0c7f8a539c0d84a9aed2f13829f5b24cde068
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>