Add 'find' command to cgpt, to search for partitions by UUID.

Review URL: http://codereview.chromium.org/2849040
diff --git a/cgpt/cgpt.c b/cgpt/cgpt.c
index d80bffe..d8604b1 100644
--- a/cgpt/cgpt.c
+++ b/cgpt/cgpt.c
@@ -26,6 +26,7 @@
   {"show", cmd_show, "Show partition table and entries"},
   {"repair", cmd_repair, "Repair damaged GPT headers and tables"},
   {"boot", cmd_boot, "Edit the PMBR sector for legacy BIOSes"},
+  {"find", cmd_find, "Locate a partition by its GUID"},
 };