Remove a warning "possibly useless use of a variable in void context"
Remove a warning "instance variable @separator not initialized"
Remove warnings "(...) interpreted as grouped expression"
Remove warnings "assigned but unused variable"
Remove a warning "assigned but unused variable" in test
Remove a warning "shadowing outer local variable - r"
Remove a warning "shadowing outer local variable - g" in examples
Merge pull request #62 from kachick/improve/remove_some_warnings

Remove some warnings