Handle unsupported image types

[dnwjn]

Features

• Added fallback for unsupported image types, which prevents the image from going through Glide and serves the source directly
• Resizer
  • Added early bail to resize() for unsupported images
• Image component
  • Added simple img fallback for unsupported image types
  • Added extra checks that verify resize() output
• Set cache driver to array for tests
• Updated tests
• Updated docs