Merge branch 'release/v0.4.6' into develop

* release/v0.4.6:
  Adding v0.4.6 notes to CHANGELOG
Adding service description for the Slack API.
The channels.list, users.list, and im.list methods are currently
available.
Updating README with ApiClient details
Fixing typos in README
Fixing code example for new Phlack()
Adding groups.list API method
Adding specs for coverage
Adding ListFiles Command to API service description
Adding ListFilesIterator
Adding examples for files.list with and without the ResourceIterator
Adding docs for files.list API method
Bumped version to 0.5.0
Adding disclaimer and acknowledgements to README
Updating description and branch aliases for composer
Merge branch 'release/v0.5.0'

* release/v0.5.0:
  Updating description and branch aliases for composer
  Adding disclaimer and acknowledgements to README
  Bumped version to 0.5.0
  Adding docs for files.list API method
  Adding examples for files.list with and without the ResourceIterator
  Adding ListFilesIterator
  Adding ListFiles Command to API service description
  Adding specs for coverage
  Adding groups.list API method
  Fixing code example for new Phlack()
  Fixing typos in README
  Updating README with ApiClient details
  Adding service description for the Slack API. The channels.list, users.list, and im.list methods are currently available.