New command line totorial for VPLG

We have just added a detailed tutorial on howto run PLCC from the command line. The document is intended for users who are new to the shell/terminal/command prompt.

If you have never run a program from the command line and want to run PLCC, start here: https://sourceforge.net/p/vplg/wiki/PLCC_from_shell/

Note that a user-friendly web server is also available. The Protein Topology Graph Library (PTGL) server gives you access to PLCC output for the whole RCSB PDB. Check it out at http://ptgl.uni-frankfurt.de/