Add tools to project for Qt Creator

Adds the tools and qmake scripts from qtwebengine to the project so
that QtCreator can find them. This is the same we did in QtWebKit.

Change-Id: I09ffdb6158adcbacd9dc4958ad199917e321498a
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

qtwebengine.pro

 load(qt_build_config)
 load(qt_parts)
+
+OTHER_FILES = \
+    tools/buildscripts/* \
+    tools/scripts/* \
+    tools/qmake/config.tests/khr/* \
+    tools/qmake/config.tests/libcap/* \
+    tools/qmake/config.tests/libvpx/* \
+    tools/qmake/config.tests/snappy/* \
+    tools/qmake/config.tests/srtp/* \
+    tools/qmake/mkspecs/features/*