Enhance profile library's parser to accept comments

Enhance profile library's parser to accept comments

This also changes syntax accepted by the profile parser.  The value of
profile relations must not contain spaces unless it is quoted;
otherwise the parser will throw an error.  Previously something like
this was allowed:

	[liboptions]
		test = foo bar

Now, the relation must be in double quotes in order to be valid, i.e.,
"foo bar".

Comments are allowed anywhere and can be started with either a ';' or
a '#' character.  The only place where comments will not be intepreted
as beginning a comment is in a quoted string.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>