allegro generator module

This version introduces multiple enhancements:

added base allegro_generator module file
added some base templates
added missing translations
added module to main page

Details of additions/deletions below:
--------------------------------------------------------------

Added:      BLUE_FRAMEWORK/modules/allegro_generator/allegro_generator.php
            -- Added --
                allegro generator main module

Added:      BLUE_FRAMEWORK/modules/allegro_generator/layouts/index.html
            -- Added --
                allegro generator main template

Added:      BLUE_FRAMEWORK/elements/layouts/common/header.html
            -- Added --
                common header

Added:      BLUE_FRAMEWORK/elements/layouts/common/footer.html
            -- Added --
                common footer

Modified:   BLUE_FRAMEWORK/cfg/lang/core_pl-PL.php
            -- Added --
                missing error translations

Modified:   BLUE_FRAMEWORK/cfg/tree.xml
            -- Added --
                allegro_generator module to index page

Modified:   BLUE_FRAMEWORK/cfg/meta.xml
            -- Updated --
                title marker replaced by title

Modified:   BLUE_FRAMEWORK/elements/layouts/index.html
            -- Added --
                header, footer and content block