Upgrading Mixpanel version to 2.0.1, setting ANALYTICS_VERSION to be 0.6.1
Making ANALYTICS_VERSION a user defined build setting which gets translated into preprocessor macro and then nsstring
Pinning to lastest SDK version rather than hardcoding 0.6.1
Added run script phase to auto-synchronize the version number in comments with version number in build setting
Adding library-version property when sending data to server