Update richtext and flowless (#3386)

Author: tobiasdiez

build.gradle

@@ -105,8 +105,8 @@ dependencies {
     compile 'de.jensd:fontawesomefx-materialdesignfont:1.7.22-4'
     compile 'de.saxsys:mvvmfx-validation:1.7.0'
     compile 'org.fxmisc.easybind:easybind:1.0.3'
-    compile 'org.fxmisc.flowless:flowless:0.5.2'
-    compile 'org.fxmisc.richtext:richtextfx:0.7-M5'
+    compile 'org.fxmisc.flowless:flowless:0.6'
+    compile 'org.fxmisc.richtext:richtextfx:0.8.1'
 
     // Cannot be updated to 9.*.* until Jabref works with Java 9
     compile 'org.controlsfx:controlsfx:8.40.14'