update INSTALL for new option --enable-debug

git-svn-id: https://svn.mcs.anl.gov/repos/parallel-netcdf/trunk@1685 c368ceb8-fd28-0410-a457-e46ee1d7cd4a
update DEVELOPER_NOTES, the steps to follow before a new release

git-svn-id: https://svn.mcs.anl.gov/repos/parallel-netcdf/trunk@1686 c368ceb8-fd28-0410-a457-e46ee1d7cd4a
add -g if debug mode is enabled

git-svn-id: https://svn.mcs.anl.gov/repos/parallel-netcdf/trunk@1687 c368ceb8-fd28-0410-a457-e46ee1d7cd4a