Make HyObject.replace more resilient

This makes it work on quoted objects
PyPI is now behind a CDN. The `--use-mirrors` option is deprecated.

See PEP 449 and https://mail.python.org/pipermail/distutils-sig/2013-May/020848.html
for more information.
Add anaphoric versions of map, filter, and foreach

Anaphoric macros reduce the need to specify a lambda by binding a
special name in a form passed as a parameter to the macro. This allows
you to write more concise code:

    (= (list (--filter (even? it) [1 2 3 4])) [2 4])

This patch just adds a few basic ones. Other forms that can be
converted to anaphoric versions include reduce, remove, enumerate,
etc.
Add --each-while and --map-when

A couple of more macros:

    hy> (--each-while [1 2 3 4 5] (< it 3) (print it))
    1
    2
    3
    hy>

```--each-while``` continues to evaluate the body form while the
predicate form is true for each element in the list.

```--map-when``` uses a predicate form to determine when to apply the
map form upon the element in the list:

    hy> (list (--map-when (even? it) (* it 3) [1 2 3 4]))
    [1, 6, 3, 12]
Make --map-when accept a predicate function instead of a form

This makes it look a little cleaner:

    (list (--map-when odd? (* it 3) [1 2 3 4 5]))
Move anaphoric macros to contrib module
Add documentation and doc strings
Fix typo in ap-each
Fix typo in ap-map-when
Remove james@agentultra.com from copyright in core/macros.py
Merge pull request #338 from agentultra/anaphoric-macros

Anaphoric macros
Rename anaphoirc.rst to anaphoric.rst
Merge pull request #341 from agentultra/master

Rename anaphoirc.rst to anaphoric.rst
docs/api:formatting fixes in `quote' and `unquote'

A newline was omitted which caused the examples not to render for quote
and unquote forms
Merge pull request #342 from theanalyst/doc-fix

docs/api:formatting fixes in `quote' and `unquote'
Merge pull request #321 from berkerpeksag/travis-use-mirrors

PyPI is now behind a CDN. The `--use-mirrors` option is deprecated.
Removing this file because it's nonfree.

 The terms aren't clear, so I'm just going to get rid of this. Sad, but
 meh.
don't test the halting problem anymore.
add the start of hacking rules
Added info about tox, so people can use it prior to a PR