webserver:  Allow to build webserver as an application

Signed-off-by: Anton D. Kachalov <mouse@yandex-team.ru>

improve beacons scan display

set mrf mode to pan coordinator

readline():  A a configuration option to enable/disable command line history; Additional cosmetic changes from code review

Added command history using up/down arrow keys.

Change the name of the local variable sigset to set to prevent name collisions with the function of the same name

Readline: Fix a configuration dependency.  If we are not echoing to the console, then we cannot support tab completion

readline/NSH: Extend the tab-completion logic so that NSH commands can also be completed by pressing the tab key

readline: Update initial readline commit -- make option configurable.  Add an interface to de-couple the readline implementation from NSH.  Misc. updates for coding style

Unix style TAB compleition, for builtin apps only