handle/copyable: Implement 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 copied or destroyed.

Tested:
    Built and run through unit tests.

Change-Id: I3d23544b2e7c8d8c6686effc03b3b7433ea18bf5
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/Makefile.am b/src/Makefile.am
index 57af82a..d45007e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -4,6 +4,8 @@
 libstdplus_la_SOURCES =
 libstdplus_la_LIBADD = $(COMMON_LIBS)
 
+nobase_include_HEADERS += stdplus/handle/copyable.hpp
+
 nobase_include_HEADERS += stdplus/handle/managed.hpp
 
 nobase_include_HEADERS += stdplus/signal.hpp