Parameters

now passing parameters in command line (purged LaTeX control characers)
removed call to image magick (png and jpg should be enough for everybody)
added control of successful pdf generation to serve error page

what's missing: 
-make picture optional
-being able to pass  accented chars as parameters to TeX ( possible with luaTeX, that handles utf8 natively, but a LuaTeX bug on the output filename is preventing me from using it)