load package environment from config files

environment variables are loaded by default from
 $HOME/etc/npkg/config.json, and
 $HOME/etc/npkg/config/$PKG.json
make sure VARDIR and TEMPDIR exists before starting
support relative package start
stream stdio
specify a logs directory
add some more interpolation variables to config
0.1.0
add peer dependency to init
specify HOST environment variable
config get/set/cat
config
0.0.3