Ignore parameters that are not output during spell-checking

[GoogleCodeExporter]

When spell-checking my documents, I need to skip a lot of cases that could be 
excluded up-front.
A good improvement would be to exclude command parameters that are not output 
in the document: 
    \documentclass[pagesize, ngerman, ...]
    \usepackage{microtype}
    \cite{RecurrencePlot:un}
    \includegraphics[width=\textwidth]{img/Rp_examples}

Although parameters that are output, like \section{Speling Error}, should of 
course be corrected.

Original issue reported on code.google.com by WittC...@googlemail.com on 28 Dec 2014 at 12:13

[GoogleCodeExporter]

This is essential since for large documents with lots of settings and packages, 
there are lot of commands and parameters that are not spelled correctly, like 
the following lines:
\usepackage[square, numbers, comma, sort&compress]{natbib}
\newcommand{\HRule}{\rule{\linewidth}{0.5mm}}
which "natbib" and "0.5mm" are not English words.

So in my opinion the following should be excluded from spell checking:
* commands
* command parameters
* comments
* URLs
* citation names

Original comment by m.mahmou...@gmail.com on 28 Jan 2015 at 12:23