rank 0.2.0

Enhanced smartrank():
- Added the freq_tiebreak argument with options "match_desc", "asc", and "desc" to control alphabetical tie-breaking when ranking character vectors by frequency.
Added a new hierarchical ranking function:
- rank_stratified() performs true stratified hierarchical ranking across multiple variables. Each variable is ranked within groups defined by all previous variables.
Added two new functions for priority-based ranking:
- rank_by_priority() assigns highest ranks to user-specified values (in the order supplied), with all remaining values tied.
- reorder_by_priority() reorders a vector so that priority values appear first, while preserving the original order of all non-priority elements.
Added code of conduct and CONTRIBUTING.md

rank 0.1.1

Fixed documentation of ties.method paramater (#2)
Vignette added describing how to sort vectors or data.frames based on the results of smartrank (#3, #4)
ties.method argument can now be used when ranking categorical variables by alphabetical order (#8)
Fixed an issue where smartrank ignored desc=TRUE when ranking categorical variables by alphabetical order (#5)