add commands for converting epub files

doc/README.Converters.md

@@ -53,7 +53,7 @@ extracting text, creating an image, and converting to pdf.
 
 Unless you run a very old version of SeedDMS, you will never need
 this command for converting text files. SeedDMS has this trivial
-converter build in.
+converter built in.
 
 ### application/pdf
 
@@ -63,7 +63,9 @@ If pdftotext takes too long on large document, then you may want to
 pass parameter `-l` to specify the last page to be converted. `-q` is
 for suppressing error/warnings send to stderr
 
-`mutool draw -F txt -q -N -o - %s`
+`mutool draw -F txt -q -N -o - '%s'`
+
+`mutool convert -F text -o - '%s'`
 
 ### application/vnd.openxmlformats-officedocument.wordprocessingml.document
 
@@ -161,6 +163,10 @@ Converting from application/x-xopp to pdf only works if the xopp file
 does not use a pdf document as a background, because this pdf is not
 stored in the xopp fіle.
 
+### application/epub+zip
+
+`mutool convert -F pdf -o "%o" "%f"`
+
 ### Many office formats
 
 As already mentioned above, `unoconv` has some disadvantages. It is
@@ -210,6 +216,10 @@ needed if the output goes to stdout.
 `pdftocairo` needs to output to stdout because the output file name passed
 to pdftocairo will be suffixed with `.png`
 
+### application/epub+zip
+
+`mutool draw -F png -w %w -q -N -o '%o' '%f' 1`
+
 ### application/postscript
 
 `convert -density 100 -resize %wx '%f[0]' 'png:%o'`