Allows USE_WHITELIST to be set vi template

Adds documentation to README.md

Remove trailing commas in metadata.json

The commas after operatingsystem compatiblity expressions created
invalid JSON that could not be properly built into a release tarball.
This commit removes each. A future commit could remove all but
operatingsystem_support from the root metadata.json and the result
of puppet module build would still produce the right metadata.

Bumps version and corrects md5sums
Merge pull request #50 from scottsuch/variablize_use_whitelist_config

Allows USE_WHITELIST to be set vi template
simplified the class dependency declaration 

Using `->` and `~>` to declare resource dependency requires less code. Also, `~>` (notify) implies require.
Merge pull request #51 from robbyt/patch-1

simplified the class dependency declaration
provide ability to enable REMOTE_USER authentication within django / graphite. useful for external authentication capabilities
use resource defaults to reduce duplication
using anchor is not required because this class is not declaring other classes
fix syntax error for multiple resources
use the pip package provider instead of exec to install python libs
the function is called defined, not declared
install graphite python packages in redhat using pip
remove anchor resources, no classes are declared, so anchor is not needed
remove os-specific install, just use the pip package provider
[] is not the same as undef
must define the variable before it can be referenced
the prereq packages must be installed using the default package provider, not pip
adding workaround for odd pip install location, see https://github.com/graphite-project/carbon/issues/86
fix copy/paste error for hack-target
remove the trailing space
adding support for custom authentication using HTTP header, as well as support for REMOTE_USER authentication, both as parameters