Introducing zipped file format

Now Pencil is able to read and write in both file formats - the old simple and the new zipped.
QuaZip library is included in Pencil source only in neccessery funtcionality area.
This Pencil version is checked only on Linux.
So far don't know if it works on other OSes.
Merge pull request #9 from shoshon/master

Introducing zipped file format