Refactor qmake SUBDIRS structure

The big swift.pro is refactored by the correct usage of SUBDIRS
template. The following additional changes are made:
- Removed '_' from all targets and folder names
- Aligned parent folder and target name

refs #461

src/plugins/simulator/simulator.pro

@@ -0,0 +1,23 @@
+load(common_pre)
+
+TEMPLATE = subdirs
+CONFIG += ordered
+
+win32 {
+    if (contains(BLACK_CONFIG, FSX) | contains(BLACK_CONFIG, FS9)) {
+        SUBDIRS += fscommon
+    }
+
+    contains(BLACK_CONFIG, FSX) {
+        SUBDIRS += fsx
+        SUBDIRS += fsxconfig
+    }
+    contains(BLACK_CONFIG, FS9) {
+        SUBDIRS += fs9
+    }
+}
+
+contains(BLACK_CONFIG, XPlane) {
+    SUBDIRS += xplane
+    SUBDIRS += xplaneconfig
+}