Merge branch 'stable-2.13'

* stable-2.13:
  Add plugin's InitStep to configure plugin during site init
  Extract sharedDirectory config key into a constant
  Extract configuration keys into constants

Change-Id: I04db03871bd6cfaa51b1e7d7670e9a6f2b59d8f6
tree: b802b5e665ce56f3689f8460fda85033dcc6b660
  1. lib/
  2. src/
  3. .buckconfig
  4. .gitignore
  5. .mailmap
  6. BUCK