Fix enableBugsnag to work with multiple configs

[tmelz]

#21 is functional, but doesn't work for cases like:

productFlavors {
    dev {
        project.bugsnag { enableBugsnag false }
    }
    prod {
        project.bugsnag { enableBugsnag true }
    }
}

because all of the project.bugsnag statements are evaluated at configuration time--only the most recent one will "stick". I'd previously mistaken this as a closure that was only evaluated at runtime--whoops.

It looks like the easiest solution for this is to make use of Groovy's extra properties; we can store the enableBugsnag value either on the ProductFlavor itself or on the BuildType:

productFlavors {
    prod {}
    dev { ext.enableBugsnag = false }
}
buildTypes {
    debug { ext.enableBugsnag = false }
    release {}
}

Then the values won't override each other and we can fetch them when we're applying the plugin to the variant. It looks like this is what Fabric is doing for Crashlytics.

---

Testing:

buildTypes {
    debug { ext.enableBugsnag = false }
    release {}
}

➜  TestApplication gw assembleDebug | grep Bugsnag
➜  TestApplication gw assembleRelease | grep Bugsnag
:app:processBugsnagReleaseManifest
:app:processBugsnagReleaseProguard
:app:uploadBugsnagReleaseMapping

productFlavors {
    prod {}
    dev { ext.enableBugsnag = false }
}
buildTypes {
    debug {}
    release {}
}

➜  TestApplication gw assembleDevDebug | grep Bugsnag
➜  TestApplication gw assembleProdDebug | grep Bugsnag
:app:processBugsnagProdDebugManifest
:app:processBugsnagProdDebugProguard
:app:uploadBugsnagProdDebugMapping
➜  TestApplication gw assembleDevRelease | grep Bugsnag
➜  TestApplication gw assembleProdRelease | grep Bugsnag
:app:processBugsnagProdReleaseManifest
:app:processBugsnagProdReleaseProguard
:app:uploadBugsnagProdReleaseMapping

productFlavors {
    prod {}
    dev { ext.enableBugsnag = false }
}
buildTypes {
    debug { ext.enableBugsnag = false }
    release {}
}

➜  TestApplication gw assembleDevDebug | grep Bugsnag
➜  TestApplication gw assembleDevDebug | grep Bugsnag
➜  TestApplication gw assembleProdDebug | grep Bugsnag
➜  TestApplication gw assembleDevRelease | grep Bugsnag
➜  TestApplication gw assembleProdRelease | grep Bugsnag
:app:processBugsnagProdReleaseManifest
:app:processBugsnagProdReleaseProguard
:app:uploadBugsnagProdReleaseMapping

[loopj]

Thanks again @tmelz! This definitely makes more sense and offers more granular control.

[loopj]

@tmelz published as v2.1.1 - thanks again!