This sets it to 1.8 instead of 1.7 as Android now allows using
1.8 java language.
Bug: 38140365
Test: Ran idegen and now java language is set to 1.8 in Intellij
Change-Id: I1a1f0970357f42c3bc5ded9b3f17692812ea130a
Also excluding prebuilt jars from classpath. These include all
previous versions of the android sdk jars. Increased heap size to 800
so google intellij plugin does not complain. Changed default
configuration to use global code style insead of per project code
style.
Change-Id: If97550000fdc282cf6d506eb80b830ff4c1b87b9