Rework the frontend and backend to allow passing a ratio value in for
UseDelta rather than having a hardcoded #define-d 0.7 value always used.
This is useful for those with fast connections, who would likely benefit
from tuning this ratio to lower values; it is also useful for general
testing purposes.
The libalpm API changes for this, but we do support the old config file
format with a no-value 'UseDelta' option; in this case we simply use the
old default of 0.7.
We clamp the ratio values to a sane range between 0.0 and 2.0, allowing
ratios above 1.0 for testing purposes.
Signed-off-by: Dan McGee <dan@archlinux.org>
b3612e9cc1