Compares two strings lexicographically

"Test".compareTo("Test") => 0

"Test1".compareTo("Test") => 1
"a".compareTo("A") => 32
"z".compareTo("a") => 25

"Test".compareTo("Test1") => -1
"a".compareTo("b") => -1
"a".compareTo("c") => -2
"a".compareTo("d") => -3