Py-interface

* allow to specify Epmd host and port number through ErlNodeOpts
Thanks to Dmitry Shestak

* Adapt to Erlang 20: Encode all atoms as UTF8, set the UTF8ATOMS
distribution flag (Erlang 20 won't accept a node witout this). Retain
decoding capability for old-format atoms, but encode to UTF-8 atoms,
which has been supported by Erlang since R16.

This also means No longer any support for Erlang R15 or ealier. (The
last Erlang R15 version was released in the end of the year 2012.)

* Bugfix unpacking of strings: they were accidentally unpacked to
bytes, now they are unpacked to strings. Also added two
utillity functions: erl_term.IODataToStr and erl_term.StrToList.
* Change type represenatation of binaries, from the ErlBinary
class, to bytes, since this ought to be a more natural fit for
Python 3.
* Improve README

* Python 3 support (only). Dropped support for Python 2.
(The changes to the packing and unpacking code, mostly,
were too pervasive, to support both Python 2 an 3
in the same code base.)

NB: This is the last version with support for Python 2
From 2.0, it is Python 3. Bugfixes might go in 1.4.x, if important enough,
but any new development is intended for Python 3 only.

* Bugfix packing of improper lists on the Python side
* In the ErlMap type, which is a dict, make ints and floats,
eg 0 and 0.0, be different keys. This differs from normal Python
dicts.
* Rework the homebrewn tests into Erlang eunit tests.
* Add some README documentation and drop the old examples dir

* Add support for encoding of new floats (8 bytes)
* Add support for encoding of bit strings
* Add support for exports (fun M:F/A)
* Add support for funs (fun(...) -> ... end, and fun X/A)
* Encode/decode depending on the peer's advertised distr flags
* Convert exceptions from old-style deprecated strings, to classes