Fix RPROMPT placement

This fixes #841

powerlevel9k.zsh-theme

@@ -1740,7 +1740,7 @@ $(print_icon 'MULTILINE_LAST_PROMPT_PREFIX')'
   fi
 
   if [[ "$POWERLEVEL9K_DISABLE_RPROMPT" != true ]]; then
-    RPROMPT='$RPROMPT_PREFIX%f%b%k$(build_right_prompt)%{$reset_color%}$RPROMPT_SUFFIX'
+    RPROMPT="${RPROMPT_PREFIX}"'%f%b%k$(build_right_prompt)%{$reset_color%}'"${RPROMPT_SUFFIX}"
   fi
 
 local NEWLINE='

test/powerlevel9k.spec

@@ -114,4 +114,23 @@ function testOverwritingIconsWork() {
   # rm -fr ~/$testFolder
 }
 
+function testNewlineOnRpromptCanBeDisabled() {
+  POWERLEVEL9K_PROMPT_ON_NEWLINE=true
+  POWERLEVEL9K_RPROMPT_ON_NEWLINE=false
+  POWERLEVEL9K_CUSTOM_WORLD='echo world'
+  POWERLEVEL9K_CUSTOM_RWORLD='echo rworld'
+  POWERLEVEL9K_LEFT_PROMPT_ELEMENTS=(custom_world)
+  POWERLEVEL9K_RIGHT_PROMPT_ELEMENTS=(custom_rworld)
+
+  powerlevel9k_prepare_prompts
+  assertEquals '$(print_icon MULTILINE_FIRST_PROMPT_PREFIX) world   $(print_icon MULTILINE_LAST_PROMPT_PREFIX) rworld ' "$(print -P ${PROMPT}${RPROMPT})"
+
+  unset POWERLEVEL9K_PROMPT_ON_NEWLINE
+  unset POWERLEVEL9K_RPROMPT_ON_NEWLINE
+  unset POWERLEVEL9K_LEFT_PROMPT_ELEMENTS
+  unset POWERLEVEL9K_RIGHT_PROMPT_ELEMENTS
+  unset POWERLEVEL9K_CUSTOM_WORLD
+  unset POWERLEVEL9K_CUSTOM_RWORLD
+}
+
 source shunit2/source/2.1/src/shunit2