updated README with deprecation notice

This project has now been subsumed by EAD Toolbox
Merged upstream branch
fixed contents formatting in README
added LICENSE file
created module ``eadtoolbox.validate`` for validating EAD

Current capability is limited to validating against the EAD 2002 DTD
made sandbox validate using a Validator object

EAD2002DTDValidator object imported from eadtoolbox.validate
created module ``eadtoolbox.transform`` for transforming EAD

Current capability is limited to transforming using XSLT
made sandbox validate using a EadTransformer objects
    
XsltEadTransformer objects imported from eadtoolbox.transform