CHANGES IN VERSION 1.2.0
 -------------------------
 
 NEW FEATURES
 
     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.
 

 
 SIGNIFICANT USER-VISIBLE CHANGES
 
     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.
 
 
 BUG FIXES
 
     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
       performance.