Any html helpfile placed at htdocs/local directory preserving their relative path from
htdocs directory will override original files. e.g. If you like to override
"htdocs/lang/en.utf8/help/pages/user/myfriends.html", place amended file at
"htdocs/local/lang/en.utf8/help/pages/user/myfriends.html", the same imples to
plugins - to override
"htdocs/artefact/resume/lang/en.utf8/help/pages/index.html" the file should be
placed at "htdocs/local/artefact/resume/lang/en.utf8/help/pages/index.html").

Signed-off-by: Ruslan Kabalin <ruslan.kabalin@luns.net.uk>