Add RAxML/7.3.0

Signed-off-by: Alan Orth <alan.orth@gmail.com>
Add qiime/1.8.0

Work in progress... only about 75% of the external deps are installed
so far.  See installation notes here:

    https://gist.github.com/alanorth/100dd95f809223ae0100

Signed-off-by: Alan Orth <alan.orth@gmail.com>