Update build-depends

Update dependencies to include new package versions. Replace wai-test
with wai-extra and bump wai dependency to >=3.0 as wai-test
functionality has now been moved into wai-extra.

Signed-off-by: Stian Ellingsen    <stian@plaimi.net>
Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Reviewed-by:   Alexander Berntsen <alexander@plaimi.net>
Remove unnecessary import and 'do' from Spec.hs

Signed-off-by: Stian Ellingsen    <stian@plaimi.net>
Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Reviewed-by:   Alexander Berntsen <alexander@plaimi.net>
Implement replacement in postTimespan

Signed-off-by: Stian Ellingsen    <stian@plaimi.net>
Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Reviewed-by:   Alexander Berntsen <alexander@plaimi.net>