mdcat-0.15.0

Added

• Release builds now perform full link-time optimization to create a smaller
  binary. We do recommend to also strip the mdcat binary.
• Render SVG images in [kitty] (see GH-114).
• Update to reqwest 0.10.
• Process file list as input (see GH-54 and GH-115, by @norman-abramovitz):
  • Add --fail flag to exit on the first error when processing a file list;
    the default behaviour is to continue with the next file in case of error.

Changed

• Replace remote_resources feature with reqwest feature to use reqwest for
  retrieving remote resources, and fall back to the curl command if reqwest
  is disabled.