Update Analytics.m

- Switch to turn logging On in Debug builds, Off in Release builds
- I believe you wanted logging to be disabled by default, and for the user to manually uncomment the line... 9410c03c3629a0da7a060c8132a0e4bb53085cb3 enabled it by default on master.
Merge pull request #15 from pkamb/patch-2

ANALYTICS_DEBUG_MODE logging turned On in Debug builds, Off in Release builds