Issue with unencoded filepaths for IIP

[birm]

This is filed here as it requires a change to camic/camic and camic/caracal.

As a test, added a file "more&less.svs"; http://localhost:4010/img/IIP/raw/?DeepZoom=/images/more%26less.svs.dzi works but caMicroscope tries http://localhost:4010/img/IIP/raw/?DeepZoom=/images/more&less.svs.dzi, which can be fixed on the viewer.
However, the slashes int the filepath cannot be such encoded; "http://localhost:4010/img/IIP/raw/?DeepZoom=%2Fimages%2Fmore%2526less.svs.dzi" fails.

This also extends to pathdb which translates its url as a special handler in caracal.

[birm]

fixes staged on develop, awaiting release