Also, simplify dependencies info now that we no longer require GNU
readline.

This allows stmhal to be compiled with MICROPY_DEBUG_PRINTERS.

To comply with Python semantics.

Previous to this patch a call such as list.append(1, 2) would lead to a
seg fault.  This is because list.append is a builtin method and the first
argument to such methods is always assumed to have the correct type.

Now, when a builtin method is extracted like this it is wrapped in a
checker object which checks the the type of the first argument before
calling the builtin function.

This feature is contrelled by MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG and
is enabled by default.

See issue #1216.

In raw REPL ">" indicates the prompt.  We originally read this character
upon entering the raw REPL, and after reading the last bit of the
output.  This patch changes the logic so the ">" is read only just
before trying to send the next command.  To make this work (and as an
added feature) the input buffer is now flushed upon entering raw REPL.

The main reason for this change is so that pyboard.py recognises the EOF
when sys.exit() is called on the pyboard.  Ie, if you run pyboard.py
with a script that calls sys.exit(), then pyboard.py will exit after
the sys.exit() is called.

esp8266: Changed esp_scan to keep the current WiFi operating mode but throw an exception if WiFi is in AP only mode

Since the commit that moved those two functions failed to update
the documentation, this is a fix for that.

MicroPython "network" module interface requires it to contains classes
to instantiate. But as we have a static network interace, make WLAN()
"constructor" just return module itself, and just make all methods
module-global functions.

Fixes regression from a previous commit.

mpconfigport.mk contains configuration options which affect the way
MicroPython is linked. In this regard, it's "stronger" configuration
dependency than even mpconfigport.h, so if we rebuild everything on
mpconfigport.h change, we certianly should of that on mpconfigport.mk
change too.

This makes all common files "port-aware" using the .. only directive.

Timer.A and Timer.B can be ORed for this purpose.