Readme: Fix link to hello_world example
Readme: Fix link to hello_world example

AnnikaH/IncludeOS,AndreasAakesson/IncludeOS,AndreasAakesson/IncludeOS,AnnikaH/IncludeOS,mnordsletten/IncludeOS,mnordsletten/IncludeOS,hioa-cs/IncludeOS,hioa-cs/IncludeOS,AndreasAakesson/IncludeOS,hioa-cs/IncludeOS,AndreasAakesson/IncludeOS,AnnikaH/IncludeOS,hioa-cs/IncludeOS,AndreasAakesson/IncludeOS,hioa-cs/IncludeOS,mnordsletten/IncludeOS,mnordsletten/IncludeOS,mnordsletten/IncludeOS,AnnikaH/IncludeOS,mnordsletten/IncludeOS,AndreasAakesson/IncludeOS,AnnikaH/IncludeOS