Simplifies the config.yaml and node configuration

[nstott]

makes the nodes config be derived by merging what's in the config.yaml and what is specified in the application.js. the config.yaml node is a map[string]map[string]bool rather then being strictly typed with Type and URI. it's possible to run without a config.yaml entirely.

for example, it's possible to do the following:

with a config.yaml containing:

nodes:
  localmongo:
    type: mongo
    uri: mongodb://localhost/boom
    namespace: boom.foo
    debug: true
  stdout:
    type: file
    uri: stdout://

and run transporter like this:
transporter eval --config test/config.yaml 'Source({name:"localmongo"}).transform({filename:"test/transformers/passthrough_and_log.js"}).save({name:"stdout"})'

as well, you can run with no config by running transporter with:
transporter eval 'Source({name:"localmongo", type: "mongo", uri:"mongodb://localhost/boom", namespace:"boom.foo", tail:true}).transform({filename:"test/transformers/passthrough_and_log.js"}).save({name:"loosefile", type:"file", uri:"file:///tmp/foo"})'

fixes #12

[jipperinbham]

any reason to leave the import commented out? vs. just removing it?

[nstott]

my bad, sloppy

[jipperinbham]

why is this a "transform error"?

[nstott]

good catch