Convert SalesforceSDK into an ARC Project

Featured in this pull request:

1) Updated to the latest version of fmdb from the parent repo.
2) Made the native SalesforceSDK project an ARC project.
3) Got rid of existing (and some new) compiler warnings in the process.
4) Generated new binaries.

Coming soon:

1) Making the SalesforceOAuth project an ARC project.
2) Making the SalesforceHybridSDK an ARC project.