This means that simply adding /bin to the end is not enough. Instead of
setting GOBIN, this version prepends things to the PATH. If GOBIN is
already set, simply prepends GOBIN to PATH. If not, appends /bin to
each component of GOPATH, then prepends that to PATH.
closes#386
Config in the config directory will need to be merged into the main
config, which is difficult to do using the *ast.Tables. Get the config
into structs as soon as possible and then merge the structs.