Sharing a Texture2D on Android always uses the same thumbnail

[cbauch]

It seems like sharing a texture uses the same filename every time. The thumbnail used for a shared image in a text message always uses the same thumbnail from the first share. Either adding an optional file name to the interface or generating unique filenames (such as appending a timestamp) every time a texture is shared would solve this issue. Currently, a workaround requires saving the texture as a file (which requires additional app permissions) then sharing it from there.

[olokobayusuf]

Fixed by #49