lang: Move bus and buffer allocators from Republic's SharedServer to Server. Expose maxLogins to ServerOptions

- Bus and Buffer allocators have always been broken for multi-client servers. This fixes this basic functionality
- maxLogins exists as a server option, but was not exposed in ServerOptions. Explicitly setting it now allows you to set how the bus and buffer ranges will be divided.

Signed-off-by: Scott Wilson <i@scottwilson.ca>
scsynth + class lib: Server returns a clientID when clients are registered with notify.

- When a client registers for notification the server sends it a clientID
- If returned clientID has not been received previously this triggers new allocators.
- When a client turns off notification the clientID is freed and can be reassigned
- If the user explicitly supplies a clientID that one is used (backwards compatible).

Signed-off-by: Scott Wilson <i@scottwilson.ca>
class lib: Add *remote method to Server

Signed-off-by: Scott Wilson <i@scottwilson.ca>
Merge pull request #1019 from supercollider/serverMultiClient

Server multi client