• charts: try to retrieve charts in .wk*, .wq* files,
• QuattroPro: add parser to .wb[12] files,
• switch to c++11,
• correct many problem detected with fuzzing,
• QuattroPro: correct reading of wq1 formula with references.

Signed-off-by: Pierre-Yves <pyu@riseup.net>

• Import a basic .wqp file in libreoffice
• Build package without having to use --disable-werror