ll: Return specific error codes
ll: SQUASH into initial implementation
apps: Implement long-advertisement

This patch implements an application that advertises a long stream of
data by splitting this into multiple pages. Then the application
advertises each page for a small time. The peer is able to reconstruct
the original data by collecting each page.

To build it, first run the configure script to generate a config.h
header with the desired Bluetooth address and data to advertise.