'SNAPCommand exit' doesn't when previous job killed.

[taltman]

Following Bill's advice on #83, I tried setting up my scripts to use the snap-aligner daemon.

Launching the daemon works, as does sending it jobs using the SNAPCommand app, but sending it the 'exit' command after a job is killed doesn't make the program exit. Instead, the daemon persists and the SNAPCommand app hangs, and I have to kill that SNAPCommand command too, and then manually kill the daemon.

$ snap-aligner daemon &                                                                                                                                                                                                                                  
[1] 49320                                                                                                                                                                                                                                                                                        
$ Welcome to SNAP version 1.0beta.23.                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                                 
SNAP in daemon mode, waiting for commands to execute                                                                                                                                                                                                                                             
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
$ SNAPCommand single snap-db unpaired-reads-no-host.fastq.gz -o test.bam                                                                                                                       
                                                                                                                                                          
Executing command: single snap-db unpaired-reads-no-host.fastq.gz -o test.bam                                                                                                                                                          
Loading index from directory... Loading index from directory...   C-c C-c^C                                                                                                                                                                                                                      
$                                                                                                                                                                                                                                                        
                                                                                                                                                                                                                                                                                                 
$ SNAPCommand exit                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
  C-c C-c^C