Breaks up a path string into its component directories.
Result = BREAK_PATH( PATHS [ /NoCurrent])
PATHS = A string containing one or more directory paths. The
individual paths are separated by commas, although in UNIX,
colons can also be used. In other words, PATHS has the same
format as !PATH, except that commas can be used as a separator
regardless of operating system.
A leading $ can be used in any path to signal that what follows
is an environmental variable, but the $ is not necessary.
Environmental variables can themselves contain multiple paths.
The result of the function is a string array of directories.
Unless the NOCURRENT keyword is set, the first element of the array is
always the null string, representing the current directory. All the
other directories will end in the correct separator character for the
current operating system.
Optional Input Keyword
/NOCURRENT = If set, then the current directory (represented by
the null string) will not automatically be prepended to the
Version 1, William Thompson, GSFC, 6 May 1993.
Added IDL for Windows compatibility.
Version 2, William Thompson, GSFC, 16 May 1995
Added keyword NOCURRENT
Version 3, William Thompson, GSFC, 29 August 1995
Modified to use OS_FAMILY
Version 4, Zarro, GSFC, 4 August 1997
Added trim to input
Fix directory character on Macintosh system A. Ferro February 2000
Use STRSPLIT instead of STR_SEP() W. Landsman July 2002
Remove VMS support W. Landsman September 2006