Currently `nomad monitor -node-id` will panic when a node-id does not
match any nodes, as there is no empty result bounds checking. Here we
return an error to the user when no nodes are found.

Adds nomad monitor command. Like consul monitor, this command allows you
to stream logs from a nomad agent in real time with a a specified log
level

add endpoint tests

Upgrade go-hclog to latest version

The current version of go-hclog pads log prefixes to equal lengths
so info becomes [INFO ] and debug becomes [DEBUG]. This breaks
hashicorp/logutils/level.go Check function. Upgrading to the latest
version removes this padding and fixes log filtering that uses logutils
Check