added support webp format (#652)

* added support webp format

* update nuke plugin with support webp format

plugins/imgview

@@ -18,7 +18,7 @@ abspath() {
 
 listimages() {
     find -L "$(dirname "$target")" -maxdepth 1 -type f -iregex \
-      '.*\(jpe?g\|bmp\|png\|gif\)$' -print0 | sort -z
+      '.*\(jpe?g\|bmp\|webp\|png\|gif\)$' -print0 | sort -z
 }
 
 view_dir() {

plugins/nuke

@@ -254,7 +254,7 @@ abspath() {
 
 listimages() {
     find -L "$(dirname "$target")" -maxdepth 1 -type f -iregex \
-      '.*\(jpe?g\|bmp\|png\|gif\)$' -print0 | sort -z
+      '.*\(jpe?g\|bmp\|webp\|png\|gif\)$' -print0 | sort -z
 }
 
 load_dir() {