Updated README.
Removed verbatim string from possible instruction operand types.
Changed instruction editor operand type selection method from hard-coded indexes to item strings.
Implemented string, Int, Int64, Double, ... operand type handler.
Fixed a bug with "None" operand type.
Replaced form Show() with ShowDialog() in some places to improve user experience and prevent bugs and issues.
Fixed bug with ContextToolStrip that would prevent it from getting shown.
Fixed reference picker form.
Refactored and improved miscellaneous code.
Prevented possible bugs and exceptions in the TreeView handler.