coyote: CGFINDPATHTO

Description
The purpose of this function is to search for a file, primarily in "resources" 
directories. It might be used, for example, to find the name of bitmap files to
use as widget button values. This program can be slow, depending upon how many 
directories it has to search. If you are looking for a *.pro file, it will probably
be faster to search for the file with File_Which. This routine is primarily used to
search for files without *.pro file extensions in places outside the normal IDL path.
Namely in "resources" directories that may reside in the main IDL directory structure
or may reside in your own application that you have built with IDL. The order of 
search is as follows::
   1. In the current directory.
   2. In the same directory as this file is found in.
   3. In the directories rooted at the IDL resource directory (IDL_DIR/resource).
   4. In the directories rooted at a resources directory found in the same directory this file is in.
   5. In the directories rooted at a resourcs directory found in the same directory this file is in.
   6. In the directories rooted at a resources directory found in the a directory one above the directory this file is in.
   7. In the directories rooted at a resource directory found in the a directory one above the directory this file is in.
   8. Anywhere in the IDL PATH. Note that a *.pro file *must* be in a directory for the directory to be on
      the IDL PATH.
Categories
Utilities
Params
filename: in, required, type=string
  The root name of the file you are searching for. For example, 'arrow.bmp'.
  Do not use a full path name to the file.
Keywords
success: out, optional, type=boolean
   On output, this keyword contains a 1 if the file was found, and a 0 otherwise.
Examples
Here is how to use this program::
  IDL> Print, cgFindPathTo('gshhs_i.b', success=s) & Print, 'success: ', s
       /home/fanning/IDL/incubator/gshhs_i.b
       success:  1
  IDL> Print, cgFindPathTo('dataviewer_splash.jpg', success=s) & print, 'success: ', s
       /home/fanning/IDL/dataviewer/resources/dataviewer_splash.jpg
       success:  1
  IDL> Print, cgFindPathTo('arc.bmp', success=s) & Print, 'success: ', s
       /usr/local/rsi/idl70/resource/bitmaps/arc.bmp
       success:  1
  IDL> Print, cgFindPathTo('toast_and_jam.txt', success=s) & Print, 'success: ', s
       success:  0
Author
FANNING SOFTWARE CONSULTING::
   David W. Fanning
   1645 Sheely Drive
   Fort Collins, CO 80526 USA
   Phone: 970-221-0438
   E-mail: david@idlcoyote.com
   Coyote's Guide to IDL Programming: http://www.idlcoyote.com
History
Change History::
   Written, 15 January 2014 by David W. Fanning.
Copyright
Copyright (c) 2014, Fanning Software Consulting, Inc.