Split texture-manager-impl files

Split texture-manager-impl files

Collect all TextureManager relative files in one folder.

And split TextureManager API's job as three files.
 - texture-manager-impl :
   Control texture loading it self. like alpha masking / synchronous / atlas / etc...
 - texture-cache-manager :
   Control internal texture caching container, external texture set, external encoded image buffers.
   Generate new TextureId, and we can access TextureInfo by TextureCacheIndex.
 - texture-async-loading-helper :
   Help async loader thread create, and callback load finished.

And make most API's input parameters from 'T' to 'const T&' if we can.

And also, make TextureManagerType namespace s.t. texture-manager-impl and textuer-cache-manager
both class need to be use, and should be shared each other.

Change-Id: Ia522a7b36da51d64282ca6b9ab4190a4e0476ad1
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>