Remove an unused local variable
Fix a number of columns

TODO:
  * accept changing a number.
  * implement paging.
Add requires
Accept options

  * -w WIDTH, --width=WIDTH
  * -h HEIGHT, --height=HEIGHT
  * --columns=NUMBER_OF_COLUMNS
  * --rows=NUMBER_OF_ROWS
Add blank lines
Fix a typo...

:columns ->
:height
Fix a typo

controll_panel ->
control_panel
Add "lib" directory to LOAD_PATH
test: add Command tests
Fix block local variable names
Add descriptions to help message
Update usage
Create a new file when don't exist a file path
Indent
Fix a variable name

file_name ->
file_path
Extract a constant "USAGE"
Support Importing data from file
Show text of image to control panel
Add "lib" directory to LOAD_PATH
Implement message