Modified the function _read_orca_allxyz so that it accepts both "generic"and "orca-flavoured" (with xyz structures separated by ">") xyz multi-structure files.

Also, fixed a bug in reading the Mayer bond order where the letter B was used as a separator to split the various records, leading to crash when the atom name is "Br, Be, Ba" etc...

Modified dihedral_scan.py and forcefield.py to support ABF scan.

Missing features:
 - automatic box sizing
 - automatic determination of # of argon
 - automatic multithread based on atom numbers for ABF run

Removed debug print statements and unused functions.

Increased md runtime for debug purposes.