Revert Still Image feature

Revert "Made sure previewImage gets exported."
	This reverts commit b3bce1496861e8ffc2534f3c1ee8b9f4f9c001d4.

Revert "Only generate previewImage if previewMedia is not already an image."
	This reverts commit 1762278a571c68db3d51780d24bbda8fcd409bd3.

Revert "Missing language bundle entry"
	This reverts commit 250490fa6fe67e9d92bd1ec3ade8e9a672175df6.

Revert "When saving a SNU with no preview image, generate one."
	This reverts commit 946fe7dde8ab8587eec40466574c21b152cdb6f8.

Revert "Added Preview Image to Snus"
	This reverts commit e53e7fb913a74a46faac61c94c85103f3dbb2363.

Revert "Made room in Snu editor preview area"
	This reverts commit 7ac312e9a1a4285d66361eb166a8b66f0a843869.

Revert "Export previewImages to XML/JSON"
	This reverts commit 8cd8cea61d4411f6acdc44133038df778c1374f5.