jai-imageio-core download and build instructions

### Instructions for downloading and building jai-imageio-core

To build the Java Advanced Imaging Image I/O Tools packages, you must checkout the jai-imageio-core CVS repository:

`cd <cvs-root-dir>```
`cvs checkout jai-imageio-core``
`

Once this is done, read the README-FIRST.txt file, then read and follow the instructions in the README-build.html file in the `<cvs-root-dir>/``jai-imageio-core` directory.