Fix remote and local confusions.

- Separate remote and local settings handling.
- Separate flow control between incoming/outgoing traffic.
- Fix connection preface handshake.

Note that currently no flow control handling is implemented on receiving DATA.
Application layer is responsible for sending WINDOW_UPDATE frame
at the right timing.
Merge pull request #22 from lepidum/draft-14-settings-sync

Fix remote and local confusions.