pgAdmin III commit: Keep better track of when external process threads

Keep better track of when external process threads are running to avoid crashes if the user closes a window at the
wrongtime. 

Branch
------
master

Details
-------
http://git.postgresql.org/gitweb?p=pgadmin3.git;a=commitdiff;h=76df8b8a5a2252e98df038aebff129ebca14ea2d
Author: Akshay Joshi <akshay.joshi@enterprisedb.com>

Modified Files
--------------
pgadmin/dlg/dlgClasses.cpp       |   19 ++++++++++++++++++-
pgadmin/include/dlg/dlgClasses.h |    4 ++++
2 files changed, 22 insertions(+), 1 deletion(-)