Properties of all px keywords. Used internally by the package.
Format
A data frame:
- keyword
- Name 
- px_function
- Function name 
- mandatory
- Is required in a PX-file 
- table_meta
- Is metadata for entire table; not individual variables or cells 
- language_dependent
- Is language dependent 
- indexed_by_contvariable
- Is indexed if CONTVARIABLE is set 
- quote_value
- Value should be quoted in PX-file 
- default_value
- Default value for mandatory keywords 
- documentation
- URL to Statistic Sweden's documentation 
- order
- Recommended order 
