ci: log time in every fold start and end

Annotating the build log with timings will help us to understand better
where the time is spend during the builds and see areas to optimize.

Switching over to the "native" bash functions in Travis, so switching
all scripts to bash.

Signed-off-by: Stefan Schmidt <s.schmidt@samsung.com>
Reviewed-by: Marcel Hollerbach <mail@marcel-hollerbach.de>
Differential Revision: https://phab.enlightenment.org/D11913