Make full example modules (issue #20)

This version introduces multiple enhancements:

added page with framework requirements
modified menu items

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

Added:      /BLUE_FRAMEWORK/elements/layouts/examples/requirements.html
            -- Added --
                requirements description

Modified:   /BLUE_FRAMEWORK/elements/layouts/examples/header.html
            -- Added --
                dropdowns with modules
            -- Updated --
                url for requirements page

Modified:   /BLUE_FRAMEWORK/cfg/lang/core_en-GB.php
            -- Added --
                requirements page translations

Modified:   /BLUE_FRAMEWORK/cfg/lang/core_pl-PL.php
            -- Added --
                requirements page translations

Modified:   /BLUE_FRAMEWORK/cfg/tree.xml
            -- Added --
                added requirements page to structure