Fix #377, where changing the text wouldn't update the ShowcaseView

Author: amlcurran

library/src/main/java/com/github/amlcurran/showcaseview/ShowcaseView.java

@@ -405,11 +405,13 @@ private void hideImmediate() {
     @Override
     public void setContentTitle(CharSequence title) {
         textDrawer.setContentTitle(title);
+        invalidate();
     }
 
     @Override
     public void setContentText(CharSequence text) {
         textDrawer.setContentText(text);
+        invalidate();
     }
 
     private void setScaleMultiplier(float scaleMultiplier) {

library/src/main/java/com/github/amlcurran/showcaseview/TextDrawer.java

@@ -112,6 +112,7 @@ public void setContentText(CharSequence details) {
             SpannableString ssbDetail = new SpannableString(details);
             ssbDetail.setSpan(textSpan, 0, ssbDetail.length(), 0);
             textString = ssbDetail;
+            hasRecalculated = true;
         }
     }
 
@@ -120,6 +121,7 @@ public void setContentTitle(CharSequence title) {
             SpannableString ssbTitle = new SpannableString(title);
             ssbTitle.setSpan(titleSpan, 0, ssbTitle.length(), 0);
             titleString = ssbTitle;
+            hasRecalculated = true;
         }
     }