added zip()

So far, don't work for strings as expected.

This is useful because tuple is closest analog of C static array.

Conflicts:
	py/builtin.c
	py/builtin.h
	py/runtime.c

By dispatching to long int methods.

Made sorted() raise an exception instead of aborting when given no arguments; moved around some things in objfun.c as a consequence

Added public domain implementations of strchr and strstr.

Initialize is_kw for dynamically allocated mp_obj_fun_native_t ojects.

This should fix issue #171

Also new vector_log png with alpha

Implement a basic str.find; fixes #67

Elaborate small-int/long-int

Set features. As per #143.

Added a hacky implementation for %g

See pyb_usart_global_debug variable.

Also did some work on USB OTG, but nothing working yet.

Long int is something which doesn't fit into SMALL_INT partion of
machine_int_t. But it's also something which doesn't fit into
machine_int_t in the first place.

We likely should make mp_obj_new_int() inline, and rely on its
encapsulated check rather than inline checks everywhere explicitly.

Also, parser for big small int values is still broken.