Mip 5150

See http://trac.openmicroscopy.org.uk/ome/ticket/5150

Add support for Z-range in projection. To test, you need to edit the url for rendered images...

 - open web image viewer for Z-stack image. Select "Max Intensity" projection. Copy the image src (right-click on image) and paste into new tab in main browser window (so you can edit the url).
 - NB: the projection is defined by the ```&p=intmax``` in the query string, and this still works as is (without range).
 - Now add a Z-range like ```&p=intmax|10:20``` and check that you get a projection of fewer slices.
 - Other invalid combinations will be ignored and the range will be restricted to 0 and sizeZ-1.
 - E.g. try ```p=intmax|-10:5```, ```p=intmax|NaN:5``` etc.