ENH: add more error conversions

Fixed py:array constructor from failing for complex types

Add complex.h to list of installed headers

The array(const buffer_info &info) constructor fails when given
complex types since their format string is 'Zd' or 'Zf' which has
a length of two and causes an error here:

if (info.format.size() != 1)
    throw std::runtime_error("Unsupported buffer format!");

Fixed by allowing format sizes of one and two.

Fix typographical errors

Add ldflags to compile command

Add debug appveyor configuration

On my system (Mac OS with custom Python installation) I had to add the ldflags argument to python-config to get things working.

Missing "is"

Change non-ASCII characters to ASCII