Revert "Split adb_main.cpp into client and daemon."

This reverts commit cf07494ac2a101c3afbe23a7d85121553f586cf7.
diff --git a/adb/usb_windows.cpp b/adb/usb_windows.cpp
index 25deb1b..1d6ec8c 100644
--- a/adb/usb_windows.cpp
+++ b/adb/usb_windows.cpp
@@ -93,6 +93,9 @@
 /// Initializes this module
 void usb_init();
 
+/// Cleans up this module
+void usb_cleanup();
+
 /// Opens usb interface (device) by interface (device) name.
 usb_handle* do_usb_open(const wchar_t* interface_name);
 
@@ -183,6 +186,9 @@
   }
 }
 
+void usb_cleanup() {
+}
+
 usb_handle* do_usb_open(const wchar_t* interface_name) {
   // Allocate our handle
   usb_handle* ret = (usb_handle*)malloc(sizeof(usb_handle));