Take in array of URLs for HttpInput, Set Logger to HttpInput
Inject timestamp into HttpInput Messages

Important to know for health checks when an endpoint comes back.
Set default severity for successful fetches to 6 (informational)
Generate internal Heka message for failed HttpInput GETs

Useful for health checks on web apps. Use case is
http://webapp.com/health is unreachable, an message of type
heka.httpdata.fail is generated with severity 1 which can be picked up
by the SmtpOutput.
Allow user defined severity for success/error messages.
Documentation update with changes.
Allow for url or urls options. Set Logger to plugin name.
Documentation to reflect changes
UUID set, meta-data Fields[] populated, Logger set to URL

- UUID set per message.
- Fields[StatusCode], Fields[Status], Fields[Protocol] populated if
HTTP GET is successful.
- Logger set to URL of request.
- Errors with HTTP GET request create minimal error message within
pipeline.
Test update
Documentation clarification
Include Content-Length as ResponseSize, Syntax Fix
Clean test run, Use pointers for channel communication
Merge pull request #576 from christianvozar/features/http-input-array

Features/httpinput-enhancements