Project restructuring (fixes macOS builds) (#198)

- Create `Include/` folder for all main projects
- Fix some issues here and there (found while moving things)
- All includes are now in `Tactility/` subfolder and must be included with that prefix. This fixes issues with clashing POSIX headers (e.g. `<semaphore.h>` versus Tactility's `Semaphore.h`)

TactilityC/Include/tt_semaphore.h

@@ -0,0 +1,50 @@
+#pragma once
+
+#include <freertos/FreeRTOS.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/** A handle that represents a semaphore instance */
+typedef void* SemaphoreHandle;
+
+/**
+ * Allocate a new semaphore instance.
+ * @param[in] maxCount the maximum counter value
+ * @param[in] initialCount the initial counter value
+ * @return the handle that represents the new instance
+ */
+SemaphoreHandle tt_semaphore_alloc(uint32_t maxCount, TickType_t initialCount);
+
+/** Free up the memory of a specified semaphore instance */
+void tt_semaphore_free(SemaphoreHandle handle);
+
+/**
+ * Attempt to acquire a semaphore (increase counter)
+ * @param[in] handle the instance handle
+ * @param[in] timeout the maximum amount of ticks to wait while trying to acquire
+ * @return true on successfully acquiring the semaphore (counter is increased)
+ */
+bool tt_semaphore_acquire(SemaphoreHandle handle, TickType_t timeout);
+
+/**
+ * Release an acquired semaphore (decrease counter)
+ * @param[in] handle the instance handle
+ * @return true on successfully releasing the semaphore (counter is decreased)
+ */
+bool tt_semaphore_release(SemaphoreHandle handle);
+
+/**
+ * Get the counter value of this semaphore instance
+ * @param[in] handle the instance handle
+ * @return the current counter value (acquisition count)
+ */
+uint32_t tt_semaphore_get_count(SemaphoreHandle handle);
+
+#ifdef __cplusplus
+}
+#endif