Also change endFilePos semantics to refer to the last character that
is *included* in the token, rather than one past the last character.
This ensures that all end* attributes have the same semantics.
The lexer can now optionally add startFilePos and endFilePos
attributes, which are offsets in to the lexed code string.
The end offset currently points one past the last character of
the token - this is pending further discussion.
The attributes are not added by default and have to be enabled
using the new 'usedAttributes' lexer option:
$lexer = new Lexer([
'usedAttributes' => [
'comments', 'startLine', 'endLine',
'startFilePos', 'endFilePos'
]
]);
