action controller builds line object from key input
rename ActionController#build_from_input to build_line_object
add description of app to gb80.coffee
add detailed comments to class declarations
rename CommandRunner class to ProgramRunner
add get_line method to ProgramLineListing
build a line object for a REM statement from text and add it to program listing
build line object from text and add to listing for all BASIC statements
refactor handler for 'enter' key event
change name of canvas element to 'gb80-console'
change 'console' and 'gb_console' variables to 'bconsole'
can type console commands or garbage into console without breaking anything
program lines entered at the console can be listed on the console with a LIST command