*{.sh,run}: changed echo_func to an alias that includes the "$", so that callers don't need to specify the "$" manually. although the original echo_func function is still there, callers need to switch over to the alias at the same time as it's defined because otherwise the "$@" would be doubled, since echo_func refers to the alias instead.

lib/util.sh: added set_make_vars alias, for use with make-target-style shell functions

lib/util.sh: mysql_cmd (): interpret an empty string for $user, $database as if they were unset

bugfix: lib/util.sh: mysql_cmd (): add --tables after specifying --databases so that future unnamed arguments are correctly interpreted as tables

bugfix: lib/util.sh: mysql_cmd (): need to use `--databases ...` rather than `--database=...` to specify the database as a named argument

bugfix: lib/util.sh: mysql_cmd (): need space before $database in command

lib/util.sh: mysql_cmd (): use $schema as $database when provided

lib/util.sh: mysql_cmd (): accept $database connection var

*{.sh,run}: use just env instead of echo_run env now that env is an auto-echoing alias

lib/util.sh: automatically echo commands that use env