master
added SpiralMatrix.java
added edited version of LetterCombinationsOfAPhoneNumber.java
added alternative solution to GuessNumberHigherOrLower.java
added PowerOfTwo.java
added brainteaser directory
finish renaming files and directories
added MinStack.java
adding HouseRobberII
adding new problems
added DailyTemperatures.java
add more problem solutions
added FirstUniqueCharacterInAString.java
test