Add "Remove" buttons for data on Texture and Mesh in NGE

[PatrickRyanMS]

In NME, TextureBlock will display a "Remove" button once a texture is loaded into the block as seen below:

In NGE, for both MeshBlock and TextureBlock once data is loaded into either block there is no "Remove" button in the UI. There are times it is necessary to remove the loaded data from the block and currently, the only way to do it is to delete the block and replace it with a new block. Mirroring the pattern in NME to add a "Remove" button on blocks that can be loaded with external data will go a long way to improving the UX of the blocks.