Initial tables support for FictionBook
Currently missing features: halign/valign and colspan/rowspan for table cells. I would like to get some feedback on the code before spending too much effort.
Test file: table.fb2
FB2 XSD describing <table> structure: https://github.com/gribuser/fb2/blob/master/FictionBook.xsd#L532-L549
Screenshot from Calibre:
Screenshot from Okular with this PR applied:
