Support Fedora 15 as a target in Makefile.install

Support Fedora 15 as a target in Makefile.install

Add Fedora 15 to the Makefile.install as a simple clone of the Fedora 14
target for now. Correct Makefile.install target names in README, and
point out that nothing special is required for Fedora 15 for PostgreSQL
9 support.

While we're in the README, rip out the Dojo toolkit install info as
packaged releases include Dojo now (we retain the developer instructions
for installing Dojo manually for git users, of course).

Signed-off-by: Dan Scott <dscott@laurentian.ca>