v0.2.2: New methods for extracting the docstring summary

Added

• We introduce the DocstringProcessor.get_extended_summary and
  DocstringProcessor.get_extended_summaryf methods to extract the
  extended summary (see the numpy documentation guidelines).
• We introduce the DocstringProcessor.get_full_description and
  DocstringProcessor.get_full_descriptionf methods to extract the
  full description (i.e. the summary plus extended summary) from a function
  docstring