Support restrictions in extended header
-ExtHeader.cs: Add enums "TagSizeRestriction", 'TextEncodingRestriction", "TextFieldsSizeRestriction", "ImageEncodingRestriction", "ImageSizeRestriction"
-ExtHeader.cs: Add properties for restrictions' enums
-ExtHeader.cs: Realise method "void ReadRestrictions(byte[] byteArray, int pointPosition)"; add methods "TagSizeRestriction GetTagSizeRestrict(byte RestrictionByte)", "TextEncodingRestriction GetTextEncodingRestriction(byte RestrictionByte)", "TextFieldsSizeRestriction GetTextFieldsSizeRestriction(byte RestrictionByte)", "ImageEncodingRestriction GetImageEncodingRestriction(byte RestrictionByte)", "ImageSizeRestriction GetImageSizeRestriction(byte RestrictionByte)"
-Frame.cs: Delete not usable fields and properties
-ExtendedHeaderTest.cs: Add test methods "TestCombExtHeader", "TestGetTagSizeRestrictionFromEnum", "TestGetTagSizeRestrictionFromInt"