Rename "Tool Chains" option page to "Compilers"

Currently it contains compiler settings only, so there's no
need to let people search for e.g. debugger settings there,
that might be considered part of the toolchain, too.

Change-Id: I458f3d1cf1784b85820f8af7604a2a004372a909
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/projectexplorer/toolchainmanager.cpp

@@ -270,7 +270,7 @@ QList<ToolChain *> ToolChainManager::restoreToolChains(const QString &fileName)
             }
         }
         if (!restored)
-            qWarning("Warning: Unable to restore tool chain '%s' stored in %s.",
+            qWarning("Warning: Unable to restore compiler '%s' stored in %s.",
                      qPrintable(ToolChainFactory::idFromMap(tcMap)),
                      qPrintable(QDir::toNativeSeparators(fileName)));
     }