inputLookup & outputLookup in to/fromJSON

Use boolean to indicate if inputLookup or outputLookup are necessary when saving to/fromJSON.

Avoids bug when training for output:{"0":1} gets interpreted as an Array when using fromJSON(net.toJSON())

Fixes https://github.com/harthur/brain/issues/22
Update json unit test
Will now use a "0" in input and output.
Merge pull request #23 from josher19/master

Handle cloned neural networks with a zero "0" in the output
Created `.gitignore` file.

Closes #25
* Ignores the node_modules directory because it's not needed in the repository.
* Ignores the DS_STORE file on Mac because it's pointless committing that every time.
* Ignores npm log file because it's unnecessary to store that in the repository.
Fixed default threshold in docs

Docs specify default errorThresh as .004 when in code it is .005
added stream training ability
Merge pull request #33 from jonmumm/patch-1

Fixed default errorThresh value in docs
Merge pull request #32 from ryansmith94/patch-1

Created `.gitignore` file.
Reduce size of main section headers in readme
remove color contrast test and 'should', 'async' and 'cradle' test dependencies
version to v0.6.3
use grunt to build browser file
update browser file download url
add simpler example of using a training stream