remove Config.java generation, use BuildConfig.java instead
rename local.properties-example -> gradle.properties-example
use BuildConfig instead of Config
update readme with instructions to generate local.properties and init gradle.properties
remove retired build files
remove unused file: proguard-project.txt
The config wasn't working correctly, that's why we firt removed proguard from gradle.
If we want to re-introduce it, we'll have to correct it.
Merge branch 'develop' into issue/1267-remove-gradle-local-properties

Conflicts:
	src/org/wordpress/android/util/WPMobileStatsUtil.java
merge with the Config.java removing branch
fix #1278: remove .settings/
update readme to correct `android update project` invocation
Merge pull request #1276 from wordpress-mobile/issue/1267-remove-gradle-local-properties

fix #1267 remove gradle local properties