ぞくぷろがぁどぉ

# To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):

#proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt

が、

# Optimization is turned off by default. Dex does not like code run

# through the ProGuard optimize and preverify steps (and performs some

# of these optimizations on its own).

 -dontoptimize

 -dontpreverify

なので、project.propertiesは

proguard.config=${sdk.dir}/tools/proguard/proguard-android-optimize.txt:proguard-project.txt

するとしあわせになれるような...