Config: added two new options to configure local builds

This will allow to ease code modifications in packages and more
flexible build configurations for development tasks.

By default the packages will need to be manually downloaded in local/.
qt5webkit: enable local build support

If local build support is globally enabled then put your qt5webkit
folder in local/, do code modifications there and rebuild with make
qt5webkit-reconfigure.
Merge pull request #36 from Metrological/local-builds

Local builds support
Merge pull request #37 from zdobersek/webkitgtk

Friday Fix Package
Revert "Config: added two new options to configure local builds"

The same can be achieved with a local.mk file.

This reverts commit b84c4641acc5e68f2cf289c1f49b7c7bdaf24c32.
Revert "qt5webkit: enable local build support"

This reverts commit fa2170db78b828894fc12ff1bb98ba59a3850965.
Improve GtkWidget redraw queueing in WaylandCompositorDispmanX

Only queue the GtkWidget redraw when a new proxy buffer is created.
This ensures that the widget gets redrawn when there's some insurance
that fresh pixel data will become available through the proxy drivers.