fix(js/main_live.js): print_output_to_console has a Boolean value instead of string
fix(js/main_live.js): print_output_to_console has a Boolean value instead of string

When a JS value is save to cookie, it's saved as a string. When we
retrieve a value of 'leanjs_print_output_to_console' from cookie, we
convert a string value (either "true" or "false") into a corresponding
Boolean value (either true or false).

close #149

soonhokong/lean-tutorial,leanprover/tutorial,avigad/tutorial,Hodapp87/cs6460_project,fpvandoorn/tutorial,fpvandoorn/tutorial,avigad/tutorial,Hodapp87/cs6460_project,Hodapp87/cs6460_project,soonhokong/lean-tutorial,leanprover/tutorial,soonhokong/lean-tutorial,avigad/tutorial,fpvandoorn/tutorial,leanprover/tutorial