Add link to RNAcanvas Code

Release v1.0.3 has a new link for editing the 2D image using RNAcanvas Code (BETA)

Release 1.0.2

r2dt-web v1.0.2 accepts input sequences in FASTA format, with an optional line for 2D structure in dot-bracket notation that supports pseudoknots, and also allows users to download the generated JSON file or Thumbnail from R2DT.