Updated requirements

Signed-off-by: Michael Greenhill <doctorjbeam@gmail.com>
Added a couple of high-level functions to AppCore that previously existed in child classes

Signed-off-by: Michael Greenhill <doctorjbeam@gmail.com>
Template::resolveTemplate() feature

Return true if the given absolute file path exists

Signed-off-by: Michael Greenhill <doctorjbeam@gmail.com>