Remove IV autogeneration

IV should be set / generated on reqest, and stored for later usage when
necessary.
Merge pull request #2 from srsbiz/remove_iv_autogeneration

Remove IV autogeneration
Change Mcrypt mode to more secure MCRYPT_MODE_CBC
Merge branch 'master' into bugfixes
Update README with generateIV new method and allow for config setting to auto generate IV
Specify PHP as the code blocks