Added printing matrix in spiral way.
Added find in matrix.

Change-Id: If4088d088fe0539d80c9de1dcdbca44f05f8e2b7
Implement a power function to raise a double to an int power.
Added "Determine the anagrams of a word in a word list".
Added "Find all prime numbers no bigger than x".
Merge pull request #4 from xiaohuazhu/develop

Develop