Removed BouncyCastle in favor of PCLCrypto. Created KeyDerivationService for Android using BouncyCastle. Applied key derivation service to CryptoService. Create iOS Test project.

src/Android/Services/BouncyCastleKeyDerivationService.cs

@@ -0,0 +1,20 @@
+using System;
+using Bit.App.Abstractions;
+using Org.BouncyCastle.Crypto.Generators;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Parameters;
+
+namespace Bit.Android.Services
+{
+    public class BouncyCastleKeyDerivationService : IKeyDerivationService
+    {
+        private const int KeyLength = 256; // 32 bytes
+
+        public byte[] DeriveKey(byte[] password, byte[] salt, uint rounds)
+        {
+            var generator = new Pkcs5S2ParametersGenerator(new Sha256Digest());
+            generator.Init(password, salt, Convert.ToInt32(rounds));
+            return ((KeyParameter)generator.GenerateDerivedMacParameters(KeyLength)).GetKey();
+        }
+    }
+}