Squashed 'ApportableFacebookSDK/' changes from e66a274..4558cf8

4558cf8 Markdown changes for legibility
2f528d7 Link to sample apps

git-subtree-dir: ApportableFacebookSDK
git-subtree-split: 4558cf8bed0673489a24160d87980078a69adae0
Merge commit '74ed016c2d79646f5e8bf2bbabed26cbc8e7f2a4' into facebook-sdk