Find token in the string.
 Finds token in the string, delimited with commas, taking into account
 nested parentheses. Outer parentheses, surrounding the whole token,
 will not be included in the final result. If no token found, on return beg==end.
- Source:
 - ../fmutl/helpers.h:168
 
- Author:
 - ATC
 
- Version:
 - 1.0
 
- Params:
 
| beg
 | pointer to the string to process. On return this pointer
 will contain start of the token.
 | 
| end
 | on return this will contain pointer to the next-to-the-last character
 of the token. On error (brackets mismatch) end will be set to 0.
 | 
 
- Returns:
 - pointer to the location in the string from which may starts next token
 or to the terminating zero character of the string.
 
- Code:
 | public extern "C" FMUTL_API const char * next_token ( |  const char * & beg , | 
|   |  const char * & end ) |