Make travis builds faster by splitting requirements into
requirements-travis.txt, which contains all the requirements necessary
for running tests, documentation related packages are omitted and added
as a part of requirements-dev.txt
Additionally .travis.yml is modified to cache pip downloads, though this
feature is yet to be rolled out for the free tier
A CONTRIBUTING.rst is added to the root of the repo, as Github
automatically recognizes this for incoming PRs
(ref: https://github.com/blog/1184-contributing-guidelines)
Most of the information is directly borrowed from the existing hacking
docs, which is restructured to refer to this file instead for
contribution guidelines
This also breaks out the PY3 only tests into their own file. We need to do this because raise from is a syntax error in PY2, so we can't rely on the previous hack of catching a HyCompileError - it would compile fine through Hy and then be a syntax error in Python.
As a result:
* functions such as `nth` should work correctly on iterators;
* `nth` will raise `IndexError` (in a fashion consistent with `get`)
when the index is out of bounds;
* `take`, etc. will raise `ValueError` instead of returning
an ambiguous value if the index is negative;
* `map`, `zip`, `range`, `input`, `filter` work the same way (Py3k one)
on both Python 2 and 3 (see #523 and #331).
Also small DRYing in try handling.
Previously, writing a bare (try (foo)) would invoke Pokemon
exception catching (gotta catch 'em all) instead of the correct
behavior, which is to raise the exception if no handler is provided.
Note that this is a cute feature of Hy, as a `try` with no `except`
is a syntax error. We avoid the syntax error here because we don't
use Python's compiler, which is the only thing that can throw
Syntax Errors. :D
Fixes#555.
