- flatten nested "lindex" structures
- merge multiple "lappend" operations
- use "lassign" instead of multiple "lindex" operations
- improve performance util_convert_line_breaks_to_html by reducing
number of regsub operations and more precise regular expressions
- use numeric comparison operator for truth value comparisons
- use "lassign" instead of multiple "lindex" operations
- reduce number of remaining "string equal" operations