Debug output for lexical analyzer

In case of error messages like:
    input buffer overflow, can't enlarge buffer because scanner uses REJECT
it is not always directly clear from which lexical analyzer (.l file) this problem comes.
This patch helps to find these problems and does the following things:
- when using the option -d lex with doxygen each time a lexical analyzer is called at the start a line like the following line will be given:
    Entering lexical analyzer: pre.l (for: ..../file.c)
  and at the end:
    Finished lexical analyzer: pre.l (for: ..../file.c)
- in case the lexical analyzer has been translated with the -d option of lex / flex the above mentioned lines will be given as part of the lexical analyzer output (to stderr) and look like:
    --entering lexical analyzer: pre.l (for: ..../file.c)
    --finished lexical analyzer: pre.l (for: ..../file.c)
Merge pull request #55 from albert-github/feature/debug_lex

Debug output for lexical analyzer
Debug output for lexical analyzer

The previous commit (pull request) was missing the debug output possibility for config.l and partial for doctokinizer.l.
The later is called on different places by means of the generic definition doctokinizerYYlex, which is declared by means of YY_DECL.
To be able to add the debug output the YY_DECL had to be redefined to be a new function and the new function, with the debug output possibility, has to be called through the original function name.
Adjust internationalization part to current situation
Merge pull request #57 from albert-github/feature/doc_build

Adjust internationalization part to current situation
Merge pull request #56 from albert-github/feature/debug_lex

Debug output for lexical analyzer
Fixed constness warning