v0.9.0

• A reader and writer are added for the MMTF file format, building on top of MMTF.jl. The interface is the same as for PDB and mmCIF files, with files either being read into the standard hierarchical structure or a MMTFDict. Gzipped files are supported. PDB, mmCIF and MMTF files can be interconverted.
• The expand_disordered flag is added to collectatoms, collectresidues, countatoms, countresidues, coordarray, writepdb, writemmcif, writemmtf and DataFrame. It determines whether disordered atoms and residues are expanded to include all entries. By default it is false except for the output functions, i.e. the last four above, where it is true by default.
• The pdbextension dictionary is changed to remove leading dots in the values.
• Improved file writing of empty elements.
• Examples are split off into a separate section in the documentation.
• A benchmark suite is added to track performance.