don't depend on APK signing

removes authentication and secure data transfer between ACardEmulator
and TCardEmulator

ACardEmulator/app/build.gradle

@@ -1,18 +1,6 @@
 apply plugin: 'com.android.application'
 
-def keystorePropertiesFile = rootProject.file("keystore.properties")
-def keystoreProperties = new Properties()
-keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
-
 android {
-    signingConfigs {
-        config {
-            keyAlias keystoreProperties['keyAlias']
-            keyPassword keystoreProperties['keyPassword']
-            storeFile file(keystoreProperties['storeFile'])
-            storePassword keystoreProperties['storePassword']
-        }
-    }
     compileSdkVersion 23
     buildToolsVersion "23.0.1"
     defaultConfig {
@@ -26,10 +14,6 @@ android {
         release {
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
-            signingConfig signingConfigs.config
-        }
-        debug {
-            signingConfig signingConfigs.config
         }
     }
     sourceSets {