Added documentation about common errors to the readme (#198)

* Added documentation about common errors to the readme

README.md

@@ -318,6 +318,100 @@ There will be one blank page before each chapter because the template is two-sid
 | :----: | :----: |
 | [![A background images on all pages](examples/page-background/page-background.png)](examples/page-background/page-background.pdf) | [![CJK Support (when using XeLaTeX)](examples/japanese/japanese.png)](examples/japanese/japanese.pdf) |
 
+## Common Errors / Issues
+
+The following section lists common errors and their solutions when using the
+Eisvogel template.
+
+### LaTeX Errors `Missing endcsname inserted` or `File x not found` when using `titlepage-background` or `logo`
+
+``` latex
+Error producing PDF.
+! Missing endcsname inserted.
+<to be read again>
+                   protect
+```
+
+``` latex
+Error producing PDF.
+! Package pdftex.def Error: File `logo\T1\textunderscoreimage.pdf' not fou
+nd: using draft setting.
+
+See the pdftex.def package documentation for explanation.
+Type  H <return>  for immediate help.
+```
+
+These errors occur when one includes a background image on the title page or a
+logo that has an underscore (`_`) in the filename.
+
+A quick fix would be to replace all underscores in the filename of the image
+with a hyphen (`-`). If the background image is specified in your YAML front
+matter like so,
+
+``` yaml
+titlepage-background: "background_image.pdf"
+```
+
+you can advise pandoc to interpret this as LaTeX and include it in the document
+without parsing.
+
+``` yaml
+titlepage-background: "`background_image.pdf`{=latex}"
+```
+
+The same fix can be used for the logo image as well:
+
+``` yaml
+logo: "`logo_image.pdf`{=latex}"
+```
+
+Corresponding issues:
+
+- [Wandmalfarbe/pandoc-latex-template#100](https://github.com/Wandmalfarbe/pandoc-latex-template/issues/100)
+- [Wandmalfarbe/pandoc-latex-template#166](https://github.com/Wandmalfarbe/pandoc-latex-template/issues/166)
+
+### LaTeX Error `auto expansion is only possible with scalable fonts`
+
+``` latex
+Error producing PDF.
+! pdfTeX error (font expansion): auto expansion is only possible with scalable
+fonts.
+\AtBegShi@Output ...ipout \box \AtBeginShipoutBox
+                                                  \fi \fi
+l.643 \begin{lstlisting}
+```
+
+This error likely occurs on Windows with MiKTeX installed. StackOverflow user
+[Krebto provided the following fix](https://tex.stackexchange.com/a/392467):
+
+> To solve the problem navigate to `C:\Program Files\MiKTeX 2.9\miktex\bin\x64` and run `updmap.exe`. The program may seem as it hangs for a while, but its probably because it tries to update the whole font tree. This solved the problem for me. After re-compiling everything should work fine.
+
+Corresponding issue:
+
+- [Wandmalfarbe/pandoc-latex-template#133](https://github.com/Wandmalfarbe/pandoc-latex-template/issues/133)
+
+### LaTeX Error `cannot find image file`
+
+``` latex
+Error producing PDF.
+! error:  (file "/tmp/tex2pdf.-be734e802ef6d0c3/""fdcfc29edcf252186f1b0a52f18f50
+43abaeb2d0".png) (pdf backend): cannot find image file '"/tmp/tex2pdf.-be734e802
+ef6d0c3/""fdcfc29edcf252186f1b0a52f18f5043abaeb2d0".png'
+!  ==> Fatal error occurred, no output PDF file produced!
+```
+
+In general this error means that LaTeX is unable to find the included image
+file. Please check all image references and file names for correctness.
+
+This error also occurs if you use an old version of Eisvogel with the package
+`grffile` and have an old LaTeX distribution installed. Please update Eisvogel
+and your LaTeX distribution.
+
+Corresponding issues:
+
+- [jgm/pandoc#5848](https://github.com/jgm/pandoc/issues/5848)
+- [Wandmalfarbe/pandoc-latex-template#149](https://github.com/Wandmalfarbe/pandoc-latex-template/issues/149)
+
 ## Credits
 
   - This template includes code for styling block quotations from [pandoc-letter](https://github.com/aaronwolen/pandoc-letter) by [Aaron Wolen](https://github.com/aaronwolen).