Adding method to update start and end of a glyph.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@15062 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Update corresponding span when updating the glyph.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@15063 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Update cds span when required.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@15064 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Hash code does not work with mutable seq symmetry and mutable seq span. Commenting it out for now.

git-svn-id: https://svn.code.sf.net/p/genoviz/code/trunk@15065 80d5a9c2-7d8c-4c9f-9369-4e03bca4d2bd
Merge remote-tracking branch 'upstream'