slider 0.3.0

• Improved reported error calls and error messages throughout the package, and
  switched from glue to cli (#168, #188).

• Index (.i) types that aren't explicitly understood by vctrs are now handled
  slightly better (#182).

• The slide_index_*() and hop_index_*() families now use vctrs::vec_rank()
  internally to compute a dense rank, which should be a little faster than the
  previous home grown approach (#177).

• New slider_plus() and slider_minus() developer facing helpers that allow
  package authors to register custom double dispatch methods to override the
  default computation of .i - .before and .i + .after when generating index
  bounds internally. This is intended to allow the clock and almanac packages to
  register methods so their custom types can be used natively in slider (#91).

• Removed ellipsis in favor of using the equivalent functions in rlang (#185).

• Removed R_forceAndCall() fallback now that R >=3.4.0 is required (#172).

• Fixed -Wstrict-prototypes warnings as requested by CRAN (#173).

• Bumped minimal version of R to >=3.4.0 to align with tidyverse standards.

• Bumped minimal version of rlang to >=1.0.6 and vctrs to >=0.5.0 (#165, #174).

• Fixed redirecting URLs.