Build wheel with all cargo features enabled

The current package disables default features. This disables most of the command line capabilities, and makes the tool difficult to use for actual development. The behavior before 97932f19 enabled all features. I believe that this change in behavior is unintentional. For context, here is a link to the code which disables the default features by default: https://github.com/PyO3/maturin/blob/2d44d1bad0c2f311932cc11d5e69852051bd9cfa/setup.py#L49.