Add .cproject and C-nature, even though it hard-codes an NDK path.
Import OpenSSL.
Implementations of PBKDF2 with SHA-1 and SHA-256.
Follow ups for testing PBKDF2 with JUnit 4.
Bug SCRYPT: Add JUnit 4 scrypt tests.
Bug SRP: Add SRP constants.
Bug STRETCH: first version of PICL key stretching.

This version is built on PBKDF2 and scrypt.  The algorithm is
described at
https://wiki.mozilla.org/Identity/AttachedServices/KeyServerProtocol#Client-Side_Key_Stretching.
Bug PRE: add HKDF.derive helper.
Bug SRP: add SRPConstants.hexModN helper.
Bug SRP: implement FxAccount.