Move all support library projects to use a single compilation unit

Also cleans up build files to include annotations as an explicit import,
set compileSdkVersion consistently to currentSdk, and remove unnecessary
lines. Removes obsolete API directories in VDC / AVDC.

Because NotificationCompatBase was using @removed APIs, updated that class
to use reflection. Also fixes method visibility in VDC / AVDC.

Bug: 29630077
Test: make and gradle builds successful
Change-Id: Ia9208246837347ce3d8df4adbe6b0ce406d3844a
diff --git a/v7/appcompat/build.gradle b/v7/appcompat/build.gradle
index 45ec21f..e6bb42b 100644
--- a/v7/appcompat/build.gradle
+++ b/v7/appcompat/build.gradle
@@ -3,6 +3,7 @@
 archivesBaseName = 'appcompat-v7'
 
 dependencies {
+    compile project(':support-annotations')
     compile project(':support-v4')
     compile project(':support-vector-drawable')
     compile project(':support-animated-vector-drawable')