Including/excluding demangled names

Added support for passing demangled C++ names to -bf-include and
-bf-exclude.  The penalty is that those options no longer accept
comma-separated function names.
Include/exclude from file

-bf-include and -bf-exclude once again accept comma-separated function
names, but these have to me mangled.  They now also accept
"@filename", where <filename> contains a list of functions, one per
line, and these can be demangled.
Allow demangled names in -bf-include/-bf-exclude

This revision combines the features of revisions 72abfc7579b3964394b2d016aeac382e019732be and 3273969acd27cd5cf3f0fad849f09bd539f009a6.  Namely, demangled function names are allowed on the command line as comma-separated arguments to -bf-include and -bf-exclude, and the @filename syntax is supported for reading lists of function names from a file.