Move tests to relevant subprojects (#615)

- Moved test projects to the parent project they belong to
- Improved test stability/corectness
- Improved recursive directory deletion by safely ignoring current- and parent-directory entries.
- Update docs

TactilityFreeRtos/Tests/Source/SemaphoreTest.cpp

@@ -0,0 +1,35 @@
+#include "doctest.h"
+#include <Tactility/Semaphore.h>
+
+using namespace tt;
+
+// We want a distinct test for 1 item, because it creates the Semaphore differently
+TEST_CASE("a Semaphore with max count of 1 can be acquired exactly once") {
+    auto semaphore = Semaphore(1);
+    CHECK_EQ(semaphore.acquire(0), true);
+    CHECK_EQ(semaphore.getAvailable(), 0);
+    CHECK_EQ(semaphore.acquire(0), false);
+    CHECK_EQ(semaphore.release(), true);
+    CHECK_EQ(semaphore.getAvailable(), 1);
+}
+
+TEST_CASE("a Semaphore with max count of 2 can be acquired exactly twice") {
+    auto semaphore = Semaphore(2);
+    CHECK_EQ(semaphore.acquire(0), true);
+    CHECK_EQ(semaphore.getAvailable(), 1);
+    CHECK_EQ(semaphore.acquire(0), true);
+    CHECK_EQ(semaphore.getAvailable(), 0);
+    CHECK_EQ(semaphore.acquire(0), false);
+    CHECK_EQ(semaphore.release(), true);
+    CHECK_EQ(semaphore.getAvailable(), 1);
+    CHECK_EQ(semaphore.release(), true);
+    CHECK_EQ(semaphore.getAvailable(), 2);
+}
+
+TEST_CASE("the semaphore count should be correct initially") {
+    auto semaphore_a = Semaphore(2);
+    CHECK_EQ(semaphore_a.getAvailable(), 2);
+
+    auto semaphore_b = Semaphore(2, 0);
+    CHECK_EQ(semaphore_b.getAvailable(), 0);
+}