Thread, Timer and flash.sh improvements (#165)

- Various improvements to Thread and Timer:
  - Remove "mark as static" option as it is unused
  - Implemented core pinning for ESP32 platforms
  - Use `TickType_t` consistently (instead of `uint32_t`)
  - Use `enum class` instead of `enum`
- Fix for `flash.sh` not working when using `pip` to install `esptool`

Tests/TactilityCore/ThreadTest.cpp

@@ -78,13 +78,13 @@ TEST_CASE("thread state should be correct") {
         &interruptable_thread,
         &interrupted
     );
-    CHECK_EQ(thread->getState(), Thread::StateStopped);
+    CHECK_EQ(thread->getState(), Thread::State::Stopped);
     thread->start();
     Thread::State state = thread->getState();
-    CHECK((state == Thread::StateStarting || state == Thread::StateRunning));
+    CHECK((state == Thread::State::Starting || state == Thread::State::Running));
     interrupted = true;
     thread->join();
-    CHECK_EQ(thread->getState(), Thread::StateStopped);
+    CHECK_EQ(thread->getState(), Thread::State::Stopped);
     delete thread;
 }