Move all core-functionality to subsurface-core

And adapt a new CMakeLists.txt file for it. On the way I've also
found out that we where double-compilling a few files. I've also
set the subsurface-core as a include_path but that was just to
reduce the noise on this commit, since I plan to remove it from
the include path to make it obligatory to specify something like

 include "subsurface-core/dive.h"

for the header files. Since the app is growing quite a bit we ended
up having a few different files with almost same name that did
similar things, I want to kill that (for instance Dive.h, dive.h,
PrintDive.h and such).

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

subsurface-core/gettextfromc.h

@@ -0,0 +1,18 @@
+#ifndef GETTEXTFROMC_H
+#define GETTEXTFROMC_H
+
+#include <QHash>
+#include <QCoreApplication>
+
+extern "C" const char *trGettext(const char *text);
+
+class gettextFromC {
+	Q_DECLARE_TR_FUNCTIONS(gettextFromC)
+public:
+	static gettextFromC *instance();
+	const char *trGettext(const char *text);
+	void reset(void);
+	QHash<QByteArray, QByteArray> translationCache;
+};
+
+#endif // GETTEXTFROMC_H