Option to ignore some macros

[sim590]

Related to #34, it would be nice if you could also ignore some macros. For instance, when using \gls from the glossaries package, one does not write entries' keys with syntactically correct words. For instance, one could write:

\newglossaryentry{textechiffre}{name={texte chiffré}, description={}}

and use therefore \gls{textechiffre} in the text which would be marked as an error as in the following example output:

* L150C11-L150C28 Faute de frappe possible trouvée (5099) 
  [lt:fr:FR_SPELLING_RULE] 
  \enquote{\gls{textechiffre}}). De façon similaire,
            ^^^^^^^^^^^^^^^^^^