Make 'V' in "Valentina" upper case on osx

This will change:
 * the filename of the application to "Valentina.app",
 * the name in the menubar to "Valentina", and
 * the about item so it says "About Valentina" instead of "About valentina"

Almost every application on OS X capitalizes their name. The only exceptions on my computer are apple's i-products (but there the second letter is upper case instead)

--HG--
branch : feature

src/app/valentina/valentina.pro

@@ -17,7 +17,11 @@ QT       += core gui widgets xml svg printsupport xmlpatterns
 TEMPLATE = app
 
 # Name of binary file
-TARGET = valentina
+macx{
+    TARGET = Valentina
+} else {
+    TARGET = valentina
+}
 
 # Use out-of-source builds (shadow builds)
 CONFIG -= debug_and_release debug_and_release_target