[LyX/master] Fix some warnings

[Jean-Marc Lasgouttes]

commit 0ad9d460681ad282bc8c40092f227f1c34a1229f
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Wed Jan 7 21:27:53 2015 +0100

    Fix some warnings

diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index 874cb17..d3523ae 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -619,16 +619,16 @@ void TextMetrics::computeRowMetrics(pit_type const pit,
                                row.dimension().wid = width;
                        } else if (is_rtl) {
                                row.dimension().wid = width;
-                               row.left_margin += w;
+                               row.left_margin += int(w);
                        }
                        break;
                }
                case LYX_ALIGN_RIGHT:
-                       row.left_margin += w;
+                       row.left_margin += int(w);
                        break;
                case LYX_ALIGN_CENTER:
                        row.dimension().wid = width - int(w / 2);
-                       row.left_margin += w / 2;
+                       row.left_margin += int(w / 2);
                        break;
                case LYX_ALIGN_LEFT:
                case LYX_ALIGN_NONE: