merged RC_1_1 int master

update Changelog

deprecate slow bdecode() function

Fix redundant bytes overflow

update build docs

bump version

apply piece priorities immediately, even though file priority updares…

… are async. save both file- and piece priorities in fast resume. when loading, apply file prios first, then piece prios

bump version to 1.1.8

update year in copyright header

improve fwd.hpp generator