Update various documentation


git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2208 ba6dc0ae-232f-0410-883f-9ebac64fc565
Several updates for debian packaging.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2209 ba6dc0ae-232f-0410-883f-9ebac64fc565
MTCP: Bug fix when running with huge environment.

The static string buffer used to store arguments and environ on restart.
On some systems, it fails to print the debug message during overflow and
causes the restarted process to hang. A proper fix would be to not rely
on the static size and come up with an alternate solution.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2210 ba6dc0ae-232f-0410-883f-9ebac64fc565
Add contrib/modify-environ plugin


git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2211 ba6dc0ae-232f-0410-883f-9ebac64fc565
contrib/README: add ptr to test/plugin


git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2212 ba6dc0ae-232f-0410-883f-9ebac64fc565