Second (smaller) set of native core functions

This rounds out the first pass at a set of core functions, adding
some that were not in the first PR.

From here I'm working on a contrib.seq and contrib.io module to
hold less obvious but maybe interesting native functions that can
move to core if desired.

This should also close out issure #150 asking for some core
functions like these.
slightly cleaner version of drop-while, could use yield-from when ready
One more commit to change the test for Python 2/3 to a macro

Note that this can't use the macro in hy.core.macros so there
is a local copy in language.hy
finally fixed access to hy.core.macros here. have to explicitly require them
Various setup.py enhancements.

- PEP8 fixes
- Use setuptools.find_packages()
- Update PyPI classifiers
- Update website URL
- Install the argparse module in Python 2.6 and before
- Delete the duplicate rply in install_requires. With the PyPI
  version, tests are failed.
Merge branch 'patch-1' of https://github.com/berkerpeksag/hy into berkerpeksag-patch-1
Coerce the contents of unquote-splice'd things to a list

This fixes the conversion issue in the following macro:

(defmacro doodle [&rest body]
  `(do ~@body))
Add test for unquote-splice behavior
Always import __future__.print_statement in hy code

This allows us to drop the print special-casing in the
compiler, and makes behavior consistent in Python2/3.
Translation of meth from Python to Hy
changed to use short version of macros
comply with hy's tao rules for getattr
Merge pull request #297 from olasd/print-function

Always import __future__.print_statement in hy code
Update README.md

Current url errors: "Choose a redirect for quickstart.html on hy.readthedocs.org"
Merge pullrequest #296
Add hy._compat module.

There was a couple of duplicate imports and type checkings in the
codebase. So I added a new module to unify all Python 2 and 3
compatibility codes.

Also, this is a somewhat common pattern in Python. See Jinja2 for
example:

https://github.com/mitsuhiko/jinja2/blob/master/jinja2/_compat.py
PY3 should really check for Python >= 3
Add @berkerpeksag to AUTHORS
Cleanup the hy.macros module

Add comments to the functions, reorder, make the file clearer
Rewrite the bootstrap macros in hy

This gets rid of the dichotomy between bootstrap.py and macros.hy,
by making both files hy modules.

I added some error checking to make the macros more resilient. The
biggest (user-visible) change is the change in cond, which now only
accepts lists as arguments. Tests updated accordingly.

Closes: #176 (whoops, no more bootstrap)