Move adb to C++.

I keep trying to clean things up and needing std::strings. Might as
well just do this now.

usb_linux_client.c is going to stay as C because GCC isn't smart
enough to deal with the designated initializers it uses (though for
some reason it is in C mode).

The Darwin files are staying as C because I don't have a way to test
that they build.

The Windows files are staying as C because while I can actually build
for them, it's slow and painful.

Change-Id: I75367d29205a9049d34460032b3bb36384f43941
diff --git a/adb/adb.h b/adb/adb.h
index 9a68871..1aeac6b 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -239,8 +239,8 @@
     fdevent fde;
     int fd;
 
-    const char *local_name;
-    const char *connect_to;
+    char *local_name;
+    char *connect_to;
     atransport *transport;
     adisconnect  disconnect;
 };
@@ -348,7 +348,7 @@
 int is_adb_interface(int vid, int pid, int usb_class, int usb_subclass, int usb_protocol);
 #endif
 
-int adb_commandline(int argc, char **argv);
+int adb_commandline(int argc, const char **argv);
 
 int connection_state(atransport *t);