Add documentation on using an unofficial version of storm

[hellais]

This clarifies my issue raised in #141

[coveralls]

Coverage remained the same at 45.23% when pulling 20ef334 on hellais:patch-1 into 78a5cd9 on Parsely:master.

[dan-blanchard]

Thanks for putting this together. I'm sure it will help other people using HDP. Could you please make this say something like:

If you wish to use streamparse with unofficial versions of storm (such as the HDP Storm) you should set :repositories in your project.clj to point to the Maven repository containing the JAR you want to use, and set the version in :dependencies to match the desired version of Storm. For example, to use the version supplied by HDP, you would set :repositories to:

:repositories {"HDP Releases" "http://repo.hortonworks.com/content/repositories/releases"}

That way it's clear the :repositories setting should be specific to whatever custom Storm JAR you want to use.

[coveralls]

Coverage remained the same at 45.23% when pulling 8da6494 on hellais:patch-1 into 78a5cd9 on Parsely:master.

[dan-blanchard]

Looks great. Thanks again! 👍