Update htmldoc patch to htmldoc-1.8.27

Note: Best to use the patched source from Ubuntu/Debian which fixes some
bugs.

Also added "Patched with margin-left.patch" text to output of
  htmldoc --version
Fix some typos in directive names
Add .gitattributes file

For specifying what not to export when running 'git archive'
Update release scripts to use git instead of svn