Improved terminology

Replaced int state with enum Tool and selectedTool variable
Merge pull request #3 from seoha/kian

Improved terminology
Merge pull request #4 from seoha/Seoregi

Seoregi
Merge pull request #5 from seoha/Seoregi

Seoregi
replaced if with switch statement
Merge pull request #6 from seoha/kian

replaced if with switch statement
fix but still has problem
append problem found and solved