Fix obj-c warnings

OLMKit.podspec

@@ -20,7 +20,7 @@ Pod::Spec.new do |s|
   s.authors            = { "Chris Ballinger" => "chrisballinger@gmail.com",
                            "matrix.org" => "support@matrix.org" }
 
-  s.ios.deployment_target = "5.0"
+  s.ios.deployment_target = "6.0"
   s.osx.deployment_target = "10.9"
 
   # Expose the Objective-C wrapper API of libolm

xcode/OLMKit/OLMInboundGroupSession.m

@@ -194,7 +194,7 @@
 {
     size_t length = olm_export_inbound_group_session_length(session);
     NSMutableData *key = [NSMutableData dataWithLength:length];
-    size_t result = olm_export_inbound_group_session(session, key.mutableBytes, key.length, messageIndex);
+    size_t result = olm_export_inbound_group_session(session, key.mutableBytes, key.length, (uint32_t)messageIndex);
     if (result == olm_error()) {
         const char *olm_error = olm_inbound_group_session_last_error(session);
         NSString *errorString = [NSString stringWithUTF8String:olm_error];

xcode/OLMKit/OLMUtility.h

@@ -36,7 +36,7 @@ FOUNDATION_EXPORT NSString *const OLMErrorDomain;
  @param signature the base64-encoded signature to be checked.
  @param key the ed25519 key.
  @param message the message which was signed.
- @param the result error if there is a problem with the verification.
+ @param error if there is a problem with the verification.
  If the key was too small then the message will be "OLM.INVALID_BASE64".
  If the signature was invalid then the message will be "OLM.BAD_MESSAGE_MAC".