Updated Server Retrieval Methods

• Updated method to retrieve PDB files
• Updated method to retrieve protein domains from InterProt (formerly PFam)

Visualize XLs in a customized PDB file

• Visualize cross-linkings in a customized PDB file.
  Now it is possible to input a PDB file instead of automatically downloading it from Uniprot or AlphaFold servers. To enable it, check the option 'Use customized PDB file' on 'XlinkCyNET Settings' .