Moving `math.hy` so it doesn't clash with library math module; band aid around issue #583 (PEP 328 non-compliance)
Enforcing dynamic scope behavior in let
Implement drop-last
Reimplement butlast in terms of drop-last
Call _wrap_value recursively on HyExpressions.

Without this, cases like:

    (defmacro foo [] `(~0))
    (foo)

throw exceptions, because the embedded zero is not a HyObject.
Add @zenhack
Add tests for _wrap_value
Added command-line utility which takes current NEWS changelog and reformats it in debian style.
Fix Python 3 re-raising
Fix flake8 errors
Fix Travis failures
Add a dedicated `lisp-if-not` / `lif-not` macro

This is in parallel to `if` / `if-not` (so not without precedent). :)
Fix #684
Add tests
Merge branch 'master' into pr/685
Fix the test decorator to return the class.
Merge branch 'master' into pr/661

Conflicts:
	AUTHORS
Merge branch 'master' into pr/666
Move reformat-changelog into scripts.
Add in Alexander Artemenko to authors.