adding this to your grdale compile "com.google.android.gms:play-services:7.5.+" means adding all play services including analytics, maps, vcm .. etc. you can add
as guides mentions:
In versions of Google Play services prior to 6.5, you had to compile
the entire package of APIs into your app. In some cases, doing so made
it more difficult to keep the number of methods in your app (including
framework APIs, library methods, and your own code) under the 65,536
limit.
From version 6.5, you can instead selectively compile Google Play
service APIs into your app. For example, to include only the Google
Fit and Android Wear APIs, replace the following line in your
build.gradle file:
compile 'com.google.android.gms:play-services:7.5.0' with these lines:
compile 'com.google.android.gms:play-services-fitness:7.5.0' compile
'com.google.android.gms:play-services-wearable:7.5.0'
https://developers.google.com/android/guides/setup