Added mark for removing unused method.
Marks for removing methods moved to SExpressionEdior.
Added "public" modifiers for using in sexptexteditor package.
Basic implementation for SExpressionEditor class.
Extending InternalTextEditor to avoid implementing all functionality again.
"public" modifier for using in sexptexteditor package.
Merge branch 'master' of https://github.com/davereyntjens/slang-ide