#3 Patch for bug 2461912: Memory leak reading PDB files

[Bruno Vecchi]

I tracked down the memory leak. It was due to a circular reference between the Chemistry::Domain (representing residues) and the Chemistry::Atom objects via the latter's attr->{pdb/res} attribute, which was being assigned a hard copy of the corresponding Chemistry::Domain, instead of a reference to it when parsing the PDB files. The attached copy of the File::PDB module seems to solve the issue.

[Bruno Vecchi]

Patched copy of File::PDB module