Fix function resolving in IDL

[nathaniel]

The existing resolve_routine calls in bdtri.pro and pdtri.pro were not
working and not necessary. Remove those calls, and put the functions
that needed resolving at the front of their files, so they are
automatically compiled when the file's main function is called. Update
common block specifications to work with the new order.

(resolve_routine calls didn't work without /COMPILE_FULL_FILE keyword, because
"When compiling a file to find a specified routine, IDL normally stops compiling when the desired routine (Name) is found. If set, COMPILE_FULL_FILE compiles the entire file."
See http://www.harrisgeospatial.com/docs/RESOLVE_ROUTINE.html )

Changing the order of the functions so the last one in the file is the one whose name matches the filename, eliminates the need for resolve_routines call entirely.

I appreciate this library, glad to contribute.
-- Nathaniel

[hainest]

Thanks, Nathaniel! To be honest, I only made the IDL version to get used to using the language. I also only tested it using GDL, so I'm not surprised there are some bugs. Glad you found it useful!