#14 load icons for the download-hyperlink in MetadataRenderer
#14 show the hyperlink OR the textarea in MetadataRenderer
#14 renamed file application-json.png
#14 format the xml document in MetadataRenderer
 #14 added methods to get images according to a char

The class ContentTypeUtils.java was renamed to ImageGetterUtils.
Furthermore two methods were added getImageForString(string) and
getImageForLetter(char). Those return a image with a letter, which is
the char or the first char of the string.
 #14 added the icons with letters
 #14 added the meta data tab to ResourceRenderer

Added a JXTaskPaneContainer as tab to the ResourceRenderer, this tab
will contain JXTaskPanes filled with MetadataRenderer.
 #14 hide the panel with content in MetadataRenderer

If the content is empty and the content url is empty then the content
panel is made invisible.
 #14 created the RepresentationRenderer

Created the RepresentationRenderer and its subpanel
SpatialAndTemporalPropertiesPanel. This subpanel was created as it can
be used later on in the RepresentationEditor.
 #14 jalopy
 #14 added data access tab to ResourceRenderer

Added a JXTaskPaneContainer which is filled with instances of
RepresentationRenderer. It is also made sure that only one JXTaskPane is
not collapsed at a time.
 #14 set insets to the panels of ResourceRenderer
 #14 added the possibility to use other icons in ImageGetterUtils.getImageForLetter()
 #14 set the proper title in ResourceRenderer
 #14 RepresentationRenderer: changed the text for the download hyperlink
 #14 avoid exceptions in ImageGetterUtils

For the methods getImageForContentType(), getImageForProtocol()
and getImageForLetter() it is first checked if a resource exists before
it is used in ImageIO.read()
 #14 see last commit