package: Add numbers 0.4.0

https://github.com/sjkaliski/numbers.js

Signed-off-by: Aki Saarinen <aki@akisaarinen.fi>
server: Send noisy observations about position

Calculate current position based on changing direction and speed, and send
noisy observations about that over JSON.

Signed-off-by: Aki Saarinen <aki@akisaarinen.fi>
client: Estimate speed and direction

Read the noisy observations sent by server and estimate speed and direction.
Speed is computed simply by looking at the first and last element for the last
10 received messages, and direction is estimated using OLS regression from the
last 10 received messages.

Signed-off-by: Aki Saarinen <aki@akisaarinen.fi>