Add textbuttons() script command, make Violet's ENTER dialogue dynamic

Violet's dialogue now looks like this:

squeak(purple)
text(purple,0,0,2)
Remember that you can press {b_map}
to check where you are on the map!
position(purple,above)
textbuttons()
speak_active

The new textbuttons() command sets the next textbox to replace {b_map}
with the map button, and {b_int} with the interact button. The
remaining keys would be added as soon as they need to be added to
ActionSets.h as well.

desktop_version/lang/en/cutscenes.xml

@@ -76,10 +76,11 @@
     <cutscene id="bigopenworldskip" explanation="">
         <dialogue speaker="purple" english="I&apos;ll be right here if you need any help!" translation=""/>
     </cutscene>
-    <cutscene id="talkpurple_intro" explanation="">
+    <cutscene id="talkpurple_intro" explanation="***ENTER is OUTDATED***">
         <dialogue speaker="player" english="I&apos;m feeling a bit overwhelmed, Doctor." translation=""/>
         <dialogue speaker="player" english="Where do I begin?" translation=""/>
         <dialogue speaker="purple" english="Remember that you can press ENTER to check where you are on the map!" translation=""/>
+        <dialogue speaker="purple" english="Remember that you can press {b_map} to check where you are on the map!" translation=""/>
         <dialogue speaker="purple" english="Look for areas where the rest of the crew might be..." translation=""/>
         <dialogue speaker="purple" english="If you get lost, you can get back to the ship from any teleporter." translation=""/>
         <dialogue speaker="purple" english="And don&apos;t worry! We&apos;ll find everyone!" translation=""/>