GH-120 Documentation updates

  Minor formatting changes, specifically capitalization of r10k at the start of sentences.
  README.mkd:
    Update documentation links to reflect the changes below.
  docs/common-patterns.mkd:
    New document showing common patterns to advise users.
  docs/dynamic-environments.mkd:
    Add link to workflow-guide.mkd.
  doc/dynamic-environments/configuration.mkd:
    Move invalid_branches description to this file.
  doc/dynamic-environments/git-environments.mkd:
    Comment on ability to use subversion.
    Clarify the details of 'how it works'.
  doc/dynamic-environments/introduction.mkd:
    Update introduction to reflect environmentpath beginning with puppet v3.5.
  doc/dynamic-environments/quickstart.mkd:
    Provide alternate method to access a dynamic environment.
  doc/dynamic-environments/usage.mkd:
    Clarify how forge modules are treated.
  doc/dynamic-environments/workflow-guide.mkd:
    Completed workflow guide.
I think this is what you were marking before, I interpreted "previous document" as git-environments.mkd (the one you had commented on previously) where I added a link to the new behavior, but you may be referencing lines 15-23 or so above. I think they are a great example of how people might do directory environments regardless of puppet version when r10k is not available, and using environmentpath on line 45 fits the current "suggestion" from the puppetlabs docs (it doesn't call out an actual suggestion but does promote the new feature). Is this satisfactory? If not, how would you like to untangle that?