Load/save for building blocks

How it will work:


1. settings will be saved to file format "SQ Building Blocks config (.sqb)" - it will be normal ZIP of XML file.
XML file will contain only <blocks> part of the standard settings file.


2. Load in Building blocks will support also loading from full SQ Config File, but it will load only blocks settings from there


3. Add support for the new .sqb file also to global Load for Settings - it will replace the current building block settings with the loaded ones, but it will not affect other settings of the program.