This is the first CL of a somewhat larger effort which, among other things,
will involve changing the emulator and ddms to talk to adb running on a
configurable port.
The port can be configured using environment variable ANDROID_ADB_SERVER_PORT.
Further CLs will also address the set of ports used for the local transport.
Change-Id: Ib2f431801f0adcd9f2dd290a28005644a36a780a
Vendor IDs are read from ~/.android/adb_usb.ini. The format is very simple:
1 number per line. First number is ID count, followed by the ID themselves.
Lines starting with # are considered comments.
Other misc changes: moved VENDOR_ID_* to usb_vendors.c to prevent direct
access. Made transport_usb.c reuse the USB constant introduced in usb_osx
(moved them to adb.h)