Renames all our .hpp HAL files to .h (#44)

Adds consistency, as the HAL was .hpp however all other code was .h.

hal/include/HAL/Task.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <pthread.h>
+#include <stdint.h>
+
+#ifndef _FUNCPTR_DEFINED
+#define _FUNCPTR_DEFINED
+#ifdef __cplusplus
+typedef int (*FUNCPTR)(...);
+/* ptr to function returning int */
+#else
+typedef int (*FUNCPTR)(); /* ptr to function returning int */
+#endif /* __cplusplus */
+#endif /* _FUNCPTR_DEFINED */
+
+#ifndef _STATUS_DEFINED
+#define _STATUS_DEFINED
+typedef int STATUS;
+#endif /* _STATUS_DEFINED */
+
+#ifndef OK
+#define OK 0
+#endif /* OK */
+#ifndef ERROR
+#define ERROR (-1)
+#endif /* ERROR */
+
+#define NULL_TASK NULL
+typedef pthread_t* TASK;
+
+extern "C" {
+// Note: These constants used to be declared extern and were defined in
+// Task.cpp. This caused issues with the JNI bindings for java, and so the
+// instantiations were moved here.
+const int32_t HAL_taskLib_ILLEGAL_PRIORITY = 22;  // 22 is EINVAL
+
+STATUS verifyTaskID(TASK task);
+STATUS setTaskPriority(TASK task, int priority);  // valid priority [1..99]
+STATUS getTaskPriority(TASK task, int* priority);
+}