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/libs/utils/textutils.cpp

@@ -80,7 +80,7 @@ QString textAt(QTextCursor tc, int pos, int length)
     return tc.selectedText().replace(QChar::ParagraphSeparator, QLatin1Char('\n'));
 }
 
-QTextCursor selectAt(QTextCursor textCursor, uint line, uint column, uint length)
+QTextCursor selectAt(QTextCursor textCursor, int line, int column, uint length)
 {
     if (line < 1)
         line = 1;