Fix all but 1 lint warnings

[rjbrock]

• Bring target sdk and build tools to current
  version

[rjbrock]

I did not suppress the TrulyRandom warning
../../src/com/koushikdutta/async/AsyncSSLSocketWrapper.java:388: Potentially insecure random numbers on Android 4.3 and older. Read https://android-developers.blogspot.com/2013/08/some-securerandom-thoughts.html for more info.

I dont see where this method is using random numbers, but I feel like this is to dangerous to ignore here.

[elevenfive]

@rjbrock try rebasing?

[rjbrock]

@elevenfive done