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).

fix: lib/sh/util.sh: verbosity_min(): usage: clarified that '' is a special value that causes $verbosity to be overwritten to ''

lib/sh/local.sh: public_schema_exists(): use a higher log_level for pg_schema_exists, to avoid all the verbose output involved in running the query

bugfix: lib/sh/local.sh: public_schema_exists(): can no longer use psql_script_vegbien for this, because using `SET search_path` (called by psql_script_vegbien) with a schema that does not exist no longer produces an error. instead, use new pg_schema_exists(), which uses a different command that does produce an error if the schema does not exist.

lib/sh/db.sh: added pg_require_schema()

lib/sh/util.sh: stderr2stdout(): documented that this redirects fd 2->1 and log_fd (but not back to 2)

bugfix: lib/sh/util.sh: stderr2stdout() use `command` before tee, which re-filters log_fd so that stderr itself is also filtered. this allows log-filtering out an otherwise-confusing benign error when using e.g. stderr_matches().

lib/sh/util.sh: added not(), for use in prefixing wrapped commands

lib/sh/db.sh: added pg_schema_exists()

lib/sh/util.sh: added stderr_matches()