Drop support for kitkat; Bump minSdk to 21

This has been dead for a while already, remove the code and bump minSdk to a
version that actually works

Signed-off-by: Aayush Gupta <aayushgupta219@gmail.com>

app/src/main/res/layout/view_dev_info.xml

@@ -30,7 +30,6 @@
         android:id="@+id/img"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:layout_margin="@dimen/margin_xxsmall"
         app:tint="?colorAccent"
         tools:src="@drawable/ic_download" />