More edits to parameter names to C API

- Function arguments with only one geometry changed from 'g1' to 'g'
- Rename 'nf' -> 'ef' for GEOSContext_setErrorHandler_rsetErrorHandler_r
- Fix typos in comments
- Clip trailing white space, and other white space consistencies
- Bump GEOSBuffer* to top of buffer related function section
- Other minor rearrangements for consistency