Better handling invalid arguments, rewrite how the arguments are handled

[ryzy]

Using docker image, when I run the following, I have errors with illegal option:

$ linode --node_name xyz --node_plan 2 --node_datacenter 7
/usr/local/bin/linode: illegal option -- -

Type --help or -h for all available options.

When called with short -x params, it works:

$ linode -n xyz -p 2 -d 7 -f Projects/linodeapi/cloud-config.yaml 

No ETCD token provided. System will generate a new one.

[ryzy]

Actually, I have exactly the same issue when I run it from the local script ./linode on Mac (Yosemite):

$ ./linode --node-name=xxx --node_plan=2 --node_datacenter=7
./linode: illegal option -- -

or without = sign in arguments:

./linode --node_name xxx --node_plan 2 --node_datacenter 7
./linode: illegal option -- -

Type --help or -h for all available options.

[ryzy]

Fixed/merged in #8