update requirements

docs/requirements.sgml

@@ -4,7 +4,7 @@
 &prog; will run on any machine that has a recent version of Java.
 This version of &prog; requires Java 1.6 at least. Most of the
 development has been done using JDK v1.6 and some of the more 
-advanced features (BamView and VCF/BCF View) require 1.6. 
+advanced features (BamView and VCF/BCF View) require Java 1.6 or higher. 
 See <XREF LINKEND="INSTALLATION"> for details on how to get Java.
   </PARA>
 </SECT1>