Change code convention in all files (issue #6)

This version introduces multiple enhancements:

fixed some code conventions, fixed documentation, fixed error description

Details of additions/deletions below:
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Modified:   /BLUE_FRAMEWORK/packages/CORE/meta_class.php
            -- Updated --
                __construct removed unused exception code from documentation

Modified:   /BLUE_FRAMEWORK/packages/CORE/loader_class.php
            -- Updated --
                _validate removed spaces

Modified:   /BLUE_FRAMEWORK/packages/CORE/lang_class.php
            -- Updated --
                setTranslationArray fixed documentation
                checkLanguage fixed code convention and return statement
                _checkLanguageCode fixed return statement

Modified:   /BLUE_FRAMEWORK/packages/CORE/globals_class.php
            -- Added --
                missing documentation fo _checkKey method
            -- Updated --
                renamed single method to _single
                renamed put method to _put
                read method to handle new name of _single method
                _createData method to handle new name of _put method

Modified:   /BLUE_FRAMEWORK/packages/CORE/exception_class.php
            -- Updated --
                showCore fixed code convention

Modified:   /BLUE_FRAMEWORK/cfg/lang/core_error_en-GB.php
            -- Updated --
                core_error_12 description

Modified:   /BLUE_FRAMEWORK/cfg/lang/core_error_pl-PL.php
            -- Updated --
                core_error_12 description