handle/managed: Implement non-copyable handle

This is a generic handle type that holds a resource and uses RAII to
call a user defined function when the resource is destroyed. A future
change will implement a smart file descriptor based on this interface.

A follow up change will implement the copyable version.

Tested:
    Built and run through unit tests.

Change-Id: Ia8da1d662319e8fb58380ed4979bcf1b74f66dfb
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/.gitignore b/.gitignore
index 205819a..4524a76 100644
--- a/.gitignore
+++ b/.gitignore
@@ -41,4 +41,5 @@
 /src/stdplus.pc
 
 # Output binaries
+/test/handle/managed
 /test/signal