CHANGES IN VERSION 1.1.8
------------------------

NEW FEATURES

    o create lower level API and rewrite higher level API

    o new geom: geom_alignment, geom_chevron, geom_arch, geom_arrow, 
                geom_arrowrect

    o redefined geom: geom_rect, geom_segment

    o new stat: stat_aggregate, stat_coverage, stat_mismatch, stat_gene, stat_table, 
                stat_stepping

    o redefined stat: stat_identity

    o new layout: layout_circle, layout_karyogram

    o tracks function are more smart and with more accessors.

    o themes provided.

    o More supported object for autoplot: VCF, ExpressionSet, GenomicRangesList.
    
SIGNIFICANT USER-LEVEL CHANGES

    o qplot changed to generic autoplot function.

    o argument use only "facets", no alias "facet_gr" or "facet" accepted.

    o plotMismatchSum will be replaced by stat_mismatch, or autoplot, BamFile.
    
Notes

    o new website for ggbio: 
      http://tengfei.github.com/ggbio
      hosting docs, tutorials and case study

    o pdf version vignette will not longer supported or just provide a short form.