Issue #265: Use only titlepage-logo but not logo

- `logo` is already used by beamer and one might want to use both
  formats (beamer and latex) without the logo appearing as a
  background image on beamer slides.

README.md

@@ -72,6 +72,10 @@ This template defines some new variables to control the appearance of the result
 
     the height of the rule on the top of the title page (in points)
 
+  - `titlepage-logo`
+
+    path to an image that will be displayed on the title page. The path is always relative to where pandoc is executed. The option `--resource-path` has no effect.
+
   - `titlepage-background`
 
     the path to a background image for the title page. The background image is scaled to cover the entire page. In the examples folder under `titlepage-background` are a few example background images.
@@ -140,10 +144,6 @@ This template defines some new variables to control the appearance of the result
 
     typeset as book
 
-  - `logo`
-
-    path to an image that will be displayed on the title page. The path is always relative to where pandoc is executed. The option `--resource-path` has no effect.
-
   - `logo-width` (defaults to `35mm`)
 
     the width of the logo. One needs to specify the width with a (TeX) unit e.g. `100pt` or `35mm`. The following units can be used:
@@ -338,7 +338,7 @@ There will be one blank page before each chapter because the template is two-sid
 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 Errors `Missing endcsname inserted` or `File x not found` when using `titlepage-background`, `logo`, or `titlepage-logo`.
 
 ``` latex
 Error producing PDF.

eisvogel.tex

@@ -321,7 +321,7 @@ $else$
 \usepackage[margin=2.5cm,includehead=true,includefoot=true,centering,$for(geometry)$$geometry$$sep$,$endfor$]{geometry}
 $endif$
 $endif$
-$if(logo)$
+$if(titlepage-logo)$
 \usepackage[export]{adjustbox}
 \usepackage{graphicx}
 $endif$
@@ -917,9 +917,9 @@ $else$
 }
 $endif$
 
-$if(logo)$
+$if(titlepage-logo)$
 \noindent
-\includegraphics[width=$if(logo-width)$$logo-width$$else$35mm$endif$, left]{$logo$}
+\includegraphics[width=$if(logo-width)$$logo-width$$else$35mm$endif$, left]{$titlepage-logo$}
 $endif$
 
 $if(titlepage-background)$

examples/title-page-logo/document.md

@@ -10,7 +10,7 @@ titlepage: true
 titlepage-text-color: "7137C8"
 titlepage-rule-color: "7137C8"
 titlepage-rule-height: 2
-logo: "logo.pdf"
+titlepage-logo: "logo.pdf"
 logo-width: 30mm
 ...