DATACMNS-363 - Support unicode characters in in query method names.

Modified the regex for prefix_template and keyword_template in PartTree in order to support arbitrary unicode characters. Before that change we didn't support unicode correctly since we assumed that a character would have a lower and upper case representation which is often not the case, e.g. in chinese.

Original pull request: #41.
DATACMNS-315 - Prepare 1.6.0.RELEASE.