LMS-1870 Making inner class Size an outer class. First tests for ImageChannelsUtilsTest.

...is/dss/generic/server/AbstractDatasetDownloadServlet.java

...sd/openbis/dss/generic/server/DatasetDownloadServlet.java

...ch/systemsx/cisd/openbis/dss/generic/shared/dto/Size.java

...systemsx/cisd/openbis/dss/etl/AbsoluteImageReference.java

...systemsx/cisd/openbis/dss/etl/IHCSImageDatasetLoader.java

...isd/openbis/dss/etl/dataaccess/HCSImageDatasetLoader.java

...openbis/dss/generic/server/images/ImageChannelsUtils.java

...openbis/dss/generic/server/images/TileImageReference.java

.../openbis/dss/screening/server/DssServiceRpcScreening.java

...bis/dss/generic/server/images/ImageChannelsUtilsTest.java

.../systemsx/cisd/openbis/dss/generic/server/images/img1.gif

.../systemsx/cisd/openbis/dss/generic/server/images/img1.jpg

.../systemsx/cisd/openbis/dss/generic/server/images/img1.png

...systemsx/cisd/openbis/dss/generic/server/images/img1.tiff