Standardize on int for line and column values

Recently tons of warnings show up for presumably "problematic"
singned <-> unsigned and size conversions.

The Qt side uses 'int', and that's the biggest 'integration surface'
for us, so instead of establishing some internal boundary between
signed and unsigned areas, push that boundary out of creator core code,
and use 'int' everywhere.

Because it reduces friction further, also do it in libcplusplus.

Change-Id: I84f3b79852c8029713e7ea6f133ffb9ef7030a70
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/cppeditor/cppfunctiondecldeflink.h

@@ -94,8 +94,8 @@ public:
     // The 'target' prefix denotes information about the remote declaration matching
     // the 'source' declaration, where we will try to apply the user changes.
     // 1-based line and column
-    unsigned targetLine = 0;
-    unsigned targetColumn = 0;
+    int targetLine = 0;
+    int targetColumn = 0;
     QString targetInitial;
 
     CppTools::CppRefactoringFileConstPtr targetFile;