Support environment variables

[mfn]

Since providing an index and an analyzer is required, it would be nice to support environment variables so there can be set some defaults to the current shell environment.

Some suggestions:

• ELYZER_ROOT_URL=http://server/9123 => same as --es http://server/9123
• ELYZER_INDEX=myIndex => same as --index myIndex
• ELYZER_ANALYZER=myAnalyzer => same as --analyzer myAnalzer`

The environment variables would be the fallback if the appropriate argument is not passed to elyzer. I.e. command line arguments "always win".

Together with #6 this would make a good fit to make this a quick and handy tool:

export ELYZER_ROOT_URL=http://server:9123
export ELYZER_INDEX=myIndex
export ELYZER_ANALYZER=myAnalyzer
$ elyzer analyze this text for me thank you

[softwaredoug]

Great.

Totally would love to see this. Don't have time now, but I'm very open to a pull request for these 2 issues.

[softwaredoug]

Fixed in #10. Released in v1.0.0. Let me know if you run into any probs!