ScaLAPACK API style

[mgates3]

Brings SLATE's ScaLAPACK API into alignment with the SLATE style guide.

• Wrap lines to 80 chars.
• Move template functions before the caller to avoid duplicating the template prototype.
• Use blas_int.
• Matrix variables are uppercase.
• Use BLAS_FORTRAN_NAME rather than duplicating the Fortran wrappers 3 times for 3 different conventions.