initial commit for epub3-to-daisy202

adapted from parts of the nordic-epub3-dtbook-migrator project:
https://github.com/josteinaj/nordic-epub3-dtbook-migrator
sample with smils, xprocspec test, improved xproc outline
a bunch of work on html5-to-html4.xsl; still some elements remaining
more work on html5-to-html4.xsl; most elements done; a few remaining
html5-to-html4: xslt and xspec finished. daisy202 sample added

the daisy202 sample should be equivalent to the epub3 sample and will be used for the xprocspec tests.
initial commit for a XProc/XSLT port of the Pipeline 1 DAISY 2.02 validator

More work on the EPUB3 to DAISY 2.02 converter made it clear that a DAISY 2.02 validator is very useful.
A DAISY 2.02 validator will be invoked after conversion to make sure the result is valid. The EPUB3 Validator (epubcheck)
will also be invoked before conversion to make sure the input is valid.

The port of the "Daisy 2.02 DTB Light Validator" is rudamentary and untested but it should run successfully.
The only thing it validates at the moment is that the SMIL clock values add up to the declared totalTime in the SMIL and NCC headers.
added daisy202-validator to pom and catalog
finished porting daisy202-validator from Pipeline 1
invoking epub3 and daisy202 validation from epub3-to-daisy202
more work
added epub3-to-daisy202.convert.xprocspec test
removed daisy202-validator and changes to epub3-validator from branch
removed validator invocations from epub3-to-daisy202
POM cleanup
Fix XSpec tests
Merge pull request #50 from daisy/epub3-to-daisy202

EPUB3 to DAISY 2.02