don't force to raise exception when an ignored region is not inside the
extract region in repeated extractions. Instead, only use the ignore
region when it is inside it.
Merge pull request #33 from kalessin/ignore_regions

don't force to raise exception when an ignored region is not inside the
add support info to README
refactor text extractor (no need to use process_markup, use region text
content instead), and ignore in html parser the xml declaration tags
Merge pull request #36 from kalessin/xmldeclaration

refactor text extractor and ignore xml declarations