Log Message:
tex-tex4ebook{,-doc}: update to 0.2c

New feature:
- \Configure{@author} - commands that produce HTML tags used inside the
  \author command may result in invalid ePub file. Local redefinitions
  of such commands may be put in this configuration to suppress their
  default behaviour.
Example: \Configure{@author}{\let\footnote\@gobble}

Bug fixes:
- fixed several issues that could result in an invalid ePub file.