Function and other signatures in comments

[ihnorton]

For spot-checking and learning it would be nice to have an option to include original C signatures as comments (or docstrings?) next to the ccall and possibly other declarations.

[visr]

Somewhat related but less general, for GDAL.jl I'm using the GDAL Doxygen documentation XML to automatically create docstrings.
The docstrings are made here and added here, resulting in docstrings like this.