Bug 940

Me & Carlos had this discussion during the RT-Embedded workshop last week. The
number of strategies in the ORB have reached bigger numbers. To configure the
ORB as a single-threaded server/client we use atleast 7 to 8 options in the
svc.conf file.  The option is going to be higher as days pass by.  Most of the
strategies in the ORB are related.  Using unrelated strategies seem to give
unexpected results. 

So the idea that Carlos ran through me was to use a single ORB option like say
"-ORBConcurrency?" that configures all these multiple  strategies in well-known,
tested configurations.  Maybe "single-threaded", "thread-per-connection", and
"thread-pool"  would suffice.  As an example the "single-threaded" configuration
would turn of all the locks, use the single threaded reactor  and use a
Read-Write connection handler.  

I suggest that we have an option "-ORBTAO_Concurrency
[single-threaded|thread-perconnection|thread-pool|custom] ".  The custom model
should allow some backward compatibility. 

If the user uses a thread-pool concurrency model we should create a thread-pool
for the user so that he/she would have less hassles in creating thread-pools.