Changed information from java 1.6 to 1.5 to work on at least on OSX 10.5.8

plugins/org.yakindu.sct.model.sexec/META-INF/MANIFEST.MF

@@ -6,7 +6,7 @@ Bundle-Version: 1.0.0.qualifier
 Bundle-ClassPath: .
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
-Bundle-RequiredExecutionEnvironment: JavaSE-1.6
+Bundle-RequiredExecutionEnvironment: J2SE-1.5
 Export-Package: org.yakindu.sct.model.sexec,
  org.yakindu.sct.model.sexec.impl,
  org.yakindu.sct.model.sexec.transformation,