Add a note about declaring properties `copy`
Merge pull request #28 from github/copy-properties

Proposal: specify that all immutable object properties should be marked "copy"
Leave a blank line after control structures
Revert "Leave a blank line after control structures"

This reverts commit 31607fba0c4d52477ce24909e0d2758d39a71db9.
Add a more general guideline about vertical whitespace
Merge pull request #30 from github/control-structure-whitespace

Vertical whitespace
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Add a more general guideline about vertical whitespace
  Revert "Leave a blank line after control structures"
  Leave a blank line after control structures
  Add a note about declaring properties `copy`

Conflicts:
	README.md