make GenomeView maxVisible and minVisible report being right at the end of the refseq if they are within less than a pixel width of it.  Fixes #24.
make GenomeView maxVisible and minVisible report being right at the end of the refseq if they are within less than a pixel width of it.  Fixes #24.

erasche/jbrowse,GreggHelt2/apollo-test,igemsoftware/Shenzhen_BGIC_0101_2013,igemsoftware/Shenzhen_BGIC_0101_2013,igemsoftware/Shenzhen_BGIC_0101_2013,SuLab/jbrowse,limeng12/jbrowse,erasche/jbrowse,nathandunn/jbrowse,erasche/jbrowse,GMOD/jbrowse,limeng12/jbrowse,limeng12/jbrowse,SuLab/jbrowse,GreggHelt2/apollo-test,Arabidopsis-Information-Portal/jbrowse,igemsoftware/Shenzhen_BGIC_0101_2013,GreggHelt2/apollo-test,limeng12/jbrowse,GreggHelt2/apollo-test,Arabidopsis-Information-Portal/jbrowse,GreggHelt2/apollo-test,GMOD/jbrowse,nathandunn/jbrowse,erasche/jbrowse,GMOD/jbrowse,SuLab/jbrowse,igemsoftware/Shenzhen_BGIC_0101_2013,Arabidopsis-Information-Portal/jbrowse,igemsoftware/Shenzhen_BGIC_0101_2013,SuLab/jbrowse,GMOD/jbrowse,igemsoftware/Shenzhen_BGIC_0101_2013,Arabidopsis-Information-Portal/jbrowse,limeng12/jbrowse,GMOD/jbrowse,Arabidopsis-Information-Portal/jbrowse,erasche/jbrowse,erasche/jbrowse,erasche/jbrowse,nathandunn/jbrowse,GreggHelt2/apollo-test,SuLab/jbrowse,igemsoftware/Shenzhen_BGIC_0101_2013,SuLab/jbrowse,limeng12/jbrowse,erasche/jbrowse,nathandunn/jbrowse,limeng12/jbrowse,Arabidopsis-Information-Portal/jbrowse,GreggHelt2/apollo-test,Arabidopsis-Information-Portal/jbrowse,nathandunn/jbrowse,SuLab/jbrowse,limeng12/jbrowse