Add WASAPI audio capture

- Add WASAPI audio capture for windows, input and output

 - Check for null pointer in os_dlopen

 - Add exception-safe 'WinHandle' and 'CoTaskMemPtr' helper classes that
   will automatically call CloseHandle on handles and call CoTaskMemFree
   on certain types of memory returned from windows functions

 - Changed the wide <-> MBS/UTF8 conversion functions so that you use
   buffers (like these functions are *supposed* to behave), and changed
   the ones that allocate to a different naming scheme to be safe

libobs/util/windows/CoTaskMemPtr.hpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2014 Hugh Bailey <obs.jim@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#pragma once
+
+template<typename T> class CoTaskMemPtr {
+	T *ptr;
+
+	inline void Clear() {if (ptr) CoTaskMemFree(ptr);}
+
+public:
+	inline CoTaskMemPtr()        : ptr(NULL) {}
+	inline CoTaskMemPtr(T *ptr_) : ptr(ptr_) {}
+	inline ~CoTaskMemPtr()                   {Clear();}
+
+	inline operator T*() const               {return ptr;}
+
+	inline CoTaskMemPtr& operator=(T* val)
+	{
+		Clear();
+		ptr = val;
+	}
+
+	inline T** operator&()
+	{
+		Clear();
+		ptr = NULL;
+		return &ptr;
+	}
+};

libobs/util/windows/WinHandle.hpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2014 Hugh Bailey <obs.jim@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#pragma once
+
+class WinHandle {
+	HANDLE handle;
+
+	inline void Clear()
+	{
+		if (handle && handle != INVALID_HANDLE_VALUE)
+			CloseHandle(handle);
+	}
+
+public:
+	inline WinHandle()               : handle(NULL)    {}
+	inline WinHandle(HANDLE handle_) : handle(handle_) {}
+	inline ~WinHandle()                                {Clear();}
+
+	inline operator HANDLE() const {return handle;}
+
+	inline WinHandle& operator=(HANDLE handle_)
+	{
+		if (handle_ != handle) {
+			Clear();
+			handle = handle_;
+		}
+
+		return *this;
+	}
+
+	inline HANDLE* operator&()
+	{
+		Clear();
+		handle = NULL;
+		return &handle;
+	}
+
+	inline bool Valid() const
+	{
+		return handle && handle != INVALID_HANDLE_VALUE;
+	}
+};