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/LockTest.cpp

@@ -0,0 +1,39 @@
+#include "doctest.h"
+#include <Tactility/Semaphore.h>
+#include <Tactility/Lock.h>
+#include <Tactility/Mutex.h>
+
+using namespace tt;
+
+TEST_CASE("withLock() locks correctly on Semaphore") {
+    auto semaphore = std::make_shared<Semaphore>(2U);
+    semaphore->withLock([semaphore](){
+        CHECK_EQ(semaphore->getAvailable(), 1);
+    });
+}
+
+TEST_CASE("withLock() unlocks correctly on Semaphore") {
+    auto semaphore = std::make_shared<Semaphore>(2U);
+    semaphore->withLock([=](){
+        // NO-OP
+    });
+
+    CHECK_EQ(semaphore->getAvailable(), 2);
+}
+
+TEST_CASE("withLock() locks correctly on Mutex") {
+    auto mutex = std::make_shared<Mutex>();
+    mutex->withLock([mutex](){
+        CHECK_EQ(mutex->lock(1), false);
+    });
+}
+
+TEST_CASE("withLock() unlocks correctly on Mutex") {
+    auto mutex = std::make_shared<Mutex>();
+    mutex->withLock([=](){
+      // NO-OP
+    });
+
+    CHECK_EQ(mutex->lock(1), true);
+    mutex->unlock();
+}