o A SequenceTrack class has been added to draw genomic sequence
      information on a Gviz plot. Possible inputs for the track are
      DNAStringSet objects or directly from BSgenome packages.

    o GeneRegionTracks can now deal with coding and non-coding regions
      by means of the feature property in combination with the
      thinBoxFeature display parameter.

    o StackedTracks now have a new display parameter 'reverseStacking'
      which reverts the horizontal ordering of stacked items. If set
      to TRUE, the lowest items are moved to the top of the stack, and
      vice versa.


    o Updated the show methods for most tracks to give more meaningful
      and more compact information about the track's
      content. Availablability of data on other chromosomes than the
      currently active one should now be indicated.

    o IdeogramTracks can now be constructed from a cytoband table via
      the new bands argument in the constructor.

    o AnnotationTrack objects now by default draw connecting lines in
      a light gray color. This feature can be controlled via the
      col.line display parameter.

    o Sliding window summarization can now deal with NA values.

    o Exporting drawGD from the name space now to allow for
      sub-classing of GdObjects in other packages.

    o When building GeneRegionTracks from TrasncriptDb objects, the
      information about UTRs and coding regions is now retained.


    o When zooming into the emty space between two grouped features,
      the connecting line will now be plotted for all classes inheriting
      from AnnotationTrack.

    o An error in calculating ylims when drawing AlignedReadTracks has
      been fixed.

    o Numerous other little fixes that mainly aim at improving