Tweaking property names; avoid unneeded triple quotes; indentation

Updated deltablast parameter list indentation to match rest of module.
This may not be strictly PEP8, but it helps for showing the property
docstrings on a single line.
Handle clang error about -mno-fused-madd under Mac OS X.

This is a workaround for Apple's incompatible Python & Clang releases,
using the C/C++ compiler environment variables to add -Qunused-arguments
to silence the clang error.

Closes issue #325.