New goformation version removing unnecessary tag reading. Fixes #30

[pesama]

Test suite:

aws-sam-local$ go test
Running Suite: AwsSamLocal Suite
================================
Random Seed: 1502647868
Will run 30 of 30 specs

••••••••••••••••••••••••••••••
Ran 30 of 30 Specs in 0.000 seconds
SUCCESS! -- 30 Passed | 0 Failed | 0 Pending | 0 Skipped PASS
ok      github.com/awslabs/aws-sam-local        3.051s

Execution of start-api:

2017/08/13 20:13:16 Connected to Docker 1.30
2017/08/13 20:13:16 Successfully parsed ../goformation/test-resources/api-backend.yaml (version 2010-09-09)
2017/08/13 20:13:16 Fetching lambci/lambda:nodejs image for nodejs runtime...
nodejs: Pulling from lambci/lambda
Digest: sha256:a868b2344ef5c6037fc2834e1d0abc014f494ec446b0cd224d13ec6836f30d52
Status: Image is up to date for lambci/lambda:nodejs
2017/08/13 20:13:18 Fetching lambci/lambda:nodejs4.3 image for nodejs4.3 runtime...
nodejs4.3: Pulling from lambci/lambda
Digest: sha256:6af9d18a022b22a5a93bcd5aca0dd1a8e837a0cd9d8940cc62ae4edc6747f517
Status: Image is up to date for lambci/lambda:nodejs4.3
2017/08/13 20:13:21 Fetching lambci/lambda:nodejs4.3 image for nodejs4.3 runtime...
nodejs4.3: Pulling from lambci/lambda
Digest: sha256:6af9d18a022b22a5a93bcd5aca0dd1a8e837a0cd9d8940cc62ae4edc6747f517
Status: Image is up to date for lambci/lambda:nodejs4.3

Mounting index.get (nodejs) at http://127.0.0.1:3000/resource/{resourceId} [GET]
Mounting index.put (nodejs4.3) at http://127.0.0.1:3000/resource/{resourceId} [PUT]
Mounting index.delete (nodejs4.3) at http://127.0.0.1:3000/resource/{resourceId} [DELETE]

You can now browse to the above endpoints to invoke your functions.
You do not need to restart/reload SAM CLI while working on your functions,
changes will be reflected instantly/automatically. You only need to restart
SAM CLI if you update your AWS SAM template.