Implementation of feature request 1410. AES_ENCRYPT w/ Salt

Implementation of feature request 1410 . Adding AES_ENCRYPTION among the various types of function.

Now when AES_ENCRYPT is selected a new textbox is loaded to take the input for salt which is later used to encrypt the string.

Please review it and guide me if there is some problem or instability in the code. I tried to minimze the GUI cluttering. and to maintain the PEAR standards, however may have left something.

(We were asked to submit a patch for GSoC 2013 before 10th, so submitted this one. Didn't know when to start, so submitted it ASAP)

Thanks