Merge pull request carpentries#163 from mawds/sortfigs

Output episode figures in correct order

Author: rgaiacs

Makefile

@@ -65,19 +65,19 @@ MARKDOWN_SRC = \
   index.md \
   CONDUCT.md \
   setup.md \
-  $(wildcard _episodes/*.md) \
+  $(sort $(wildcard _episodes/*.md)) \
   reference.md \
-  $(wildcard _extras/*.md) \
+  $(sort $(wildcard _extras/*.md)) \
   LICENSE.md
 
 # Generated lesson files in the order they appear in the navigation menu.
 HTML_DST = \
   ${DST}/index.html \
   ${DST}/conduct/index.html \
   ${DST}/setup/index.html \
-  $(patsubst _episodes/%.md,${DST}/%/index.html,$(wildcard _episodes/*.md)) \
+  $(patsubst _episodes/%.md,${DST}/%/index.html,$(sort $(wildcard _episodes/*.md))) \
   ${DST}/reference/index.html \
-  $(patsubst _extras/%.md,${DST}/%/index.html,$(wildcard _extras/*.md)) \
+  $(patsubst _extras/%.md,${DST}/%/index.html,$(sort $(wildcard _extras/*.md))) \
   ${DST}/license/index.html
 
 ## lesson-md        : convert Rmarkdown files to markdown