How much slower is Secure preferences over using Standard Shared preferences?

[scottyab]

Test using hugo and/or performance tools to answer the question "How much slower is Secure preferences over using Standard Shared preferences?"

The main methods to focus on:

• Init
  • without user password
  • default
  • With supplied key
  • existing pref file
• getString
• putString

[scottyab]

See issue #18 for more details on how to speed up (but also reduce security)