v1.2.0

Changes from v1.1.1:

• Add relocate() verb for repositioning and renaming columns.
• Add derive() verb before and after options to position new derived columns.
• Add matches(), startswith(), endswith() selection helpers.
• Add op.recode() function to map input values to recoded values.
• Add limit and offset arguments to table scan() method.
• Add List and Struct type support to fromArrow(). Extracts nested values to arrays and objects, respectively.
• Add offset option for output formats such as toCSV(), toHTML(), etc.
• Add null option to toHTML() to specialize formatting of null and undefined values.