Log Message:
tex-l3packages{,-doc}: update to 2018

Release 2017-12-05

 - Fix loading of l3str-format

 - Fix handling of \iow_newline: in \iow_wrap:nnnN

 - \cs_generate_variant:Nn now warns on incorrect variant
   relationships

 - Better recovery by \dim_set:Nn, etc., if passed
   skip expressions

 - Better handling of global/local consistency in variable
   setting

 - String mappings now include space characters

 - Revise l3doc to no longer require "[aux]" (deprecated) or
   "[int]" in code mark up: "[int]" is retained for cases where
   auto-detection of internals is not possible

 - Deprecate \token_new:Nn

 - Documentation improvements