Release 0.10.6

Features

• Add full support for Brazilian Portuguese. [#139]
• Add option precision to to_words. [#134] (@neodelf) (assignee: @neodelf)

Bugs

• Fix README typo for 231 in French. (assignee: @poilon)
• Fix big numbers in Spanish. [#129] (@jlduran) (assignee: @jlduran)
• Fix typo for number twenty-one in Spanish. [#127] (@jlduran) (assignee: @jlduran)