Applied patch from Teofilis Martisius to improve performance.

Also removed some unused files and fixed the which needed a small change
after the previous patch to build.xml.

 Modified Files:
 	jdbc/Makefile jdbc/org/postgresql/core/Encoding.java
 	jdbc/org/postgresql/jdbc1/AbstractJdbc1Connection.java
 Removed Files:
 	jdbc/utils/CheckVersion.java jdbc/utils/buildDriver
 	jdbc/utils/changelog.pl