Lots of changes to make installation more flexible & user friendly.

Lots of changes to make installation more flexible & user friendly.

Generalized out a lot of the leftover phys201 content, replacing it
with dummy content.  Now the test coursepage doesn't reveal any email
addresses, names of real people, etc.

Moved all the course information that used to be spread through the
text of index.shtml and in quarter.php over to a new course.xml file.
This provides a centralized location for updates, which are then
included in the page bodies and headers for free :).

Tagged locations of example patter and dummy information in the html
directory with "...", so you won't miss any dummy info if you adjust
things near the locations turned up by a
  grep -r '[.][.][.]' html/

Reactivated contact.shtml and redirected the Contact links to point to
it, because most users will not have a contact page in the parent
directory as I do.

announcements.shtml now handles a missing atom.xml gracefully, which I
imagine will be a common occurrence for new users.

Assorted updates to README files, as well as the addition of
REAMDE.newbie, which I phrased to be more supportive to the HTML-wary
;).

Added html-includes.sh, which adapts the standard source to handle
some SSI-parsing problems that poke up occasionally.  I don't know why
yet, but the adjusted source avoids them.

Added local-install.sh, which adapts the standard source to handle
INSTALL_DIR on the same host as the source.

See the comments at the top of both shell scripts for more details.