Makefile tweaks

Modify set tests to print sorted sets directly

Add tests for sorted() function

instead of creating temporary lists and sorting those in-place

and check that sorted(list) produces same output as list.sort()

No longer needed after recent change which guarantees that mp_set_init()
will allocate exact number of slots requested.

Seems that this fixes all set tests.

So, pip-micropython can/should be run as normal pip:

    pip-micropython install micropython-unittest

With dict being unordered of course.

Sure, it's O(n^2).

Two things: 1) set flags in copy properly; make mp_map_init() not be too
smart and do something with requested alloc size. Policy of using prime
numbers for alloc size is high-level policy which should be applied at
corresponding high levels. Low-level functions should just do what they're
asked to, because they don't have enough context to be smarter than that.
For example, munging with alloc size of course breaks dict copying (as
changing sizes requires rehashing).

On x64, native emitter now passes 70 of the tests.

Also add command line option to unix port to select emitter.

Based on the discussion in #433. mp_load_attr() is critical-path function,
so any extra check will slowdown any script. As supporting default val
required only for getattr() builtin, move correspending implementation
there (still as a separate function due to concerns of maintainability
of such almost-duplicated code instances).

This is to reduce ROM usage.  stream_p is used in file and socket types
only (at the moment), so seems a good idea to make the protocol
functions a pointer instead of the actual structure.

It saves 308 bytes of ROM in the stmhal/ port, 928 in unix/.

This makes isinstance(X, object) and issubclass(X, object) true for all
X.

Finishes addressing issue #424.

In the end this was a very neat refactor that now makes things a lot
more consistent across the py code base.  It allowed some
simplifications in certain places, now that everything is a dict object.

Also converted builtins tables to dictionaries.  This will be useful
when we need to turn builtins into a proper module.

Towards addressing issue #424.

Had a small increase to ROM usage (order 60 bytes).

Implement del