Pcetk 1.0 (release for JCIM)

A release of Pcetk representing the state of the project as described in our article:
Feliks, M.; Field, M. "Pcetk: A pDynamo-based Toolkit for Protonation State Calculations in Proteins."
J. Chem. Inf. Model. 2015, 55, pp. 2288-2296 <Link to the article>