File discovery: also include the base directory

This is a regression introduced in e834585 which prevented Pootle's
terminology feature from working properly when the app was deployed using
a git clone.
Changed rc parsing to use Pyparsing library to get a better aproach.
Now you can to not specify a language to get strings of all languages.
po2rc now parse menu, dialogs, string tables, the language and output a
very similar rc file like the template but don't translate its strings.
Added STRINGTABLES translations, fix dialogs and minor refactorization.

 * Added the translation of the STRINGTABLEs commands.
 * Refactor the generation of names for msgids to methods so it can be
reused and are more readables.
 * Fixed translation of dialog captions and lists.
 * Change the handle of file encondings.
Don't add po unit when removing duplicates and they are identical (msgid
and context).
All types of resource statements are translated.

Added the menu, popup and menuitems to be translated.
Fixed some problems when parsing options list with "NOT" modifier.
Fixed the rest of statements translations.