moved everything into /trunk/ to create the standard svn layout, for use with tools that require this (eg. git-svn). IMPORTANT: do NOT do an `svn up`. instead, re-use your working copy's existing files with `svn switch` (http://svnbook.red-bean.com/en/1.6/svn.ref.svn.c.switch.html).
opts.py: get_env_var(): default defaults to None
opts.py: env_flag(): Added support for default value if unset
opts.py: Added env_names usage support to env_flag()
opts.py: Call an error handler if an env var isn't set
Moved everything in scripts to root. inputs_Makefile: Don't run "all" when installing.
map: Implemented DB input support for querying a single table
map: Allow db config vars to be optional. SALVIAS_db test: Changed to use salvias_plots and XPath mapping syntax.
Moved env usage string creation to opts.py. Changed db config var names to use in/out instead of from/to.
Moved options-processing code to opts.py: Added opts.py