Implements nicer angle conversion using FromPrimitive.

This avoids the hacks I was using earlier and makes the code much
cleaner overall. This also makes implementations for conversion
among all but Clock-type angles.

Signed-off-by: Aaron Jacobs <atheriel@gmail.com>
Reorganizes the project into a single file.

This also includes a variety of fixes in the metadata, stability,
and so on.

Signed-off-by: Aaron Jacobs <atheriel@gmail.com>
Fixes conversion bugs and adds much better test coverage for them.

Signed-off-by: Aaron Jacobs <atheriel@gmail.com>
Implements Add and Sub by hand as concatenate operations.

Also adds an unwrap() method for angles to retreive the internal
value.

This commit removes the macro-generated operators. Div and Mul don't
make sense for angles anyway.

Signed-off-by: Aaron Jacobs <atheriel@gmail.com>
Adds better documentation, both inline and to the README.

Signed-off-by: Aaron Jacobs <atheriel@gmail.com>