Add csv output option to crucible-verify-raw

[leftwo]

Added an option to crucible-verify-raw that will produce csv output instead of a formatted print.
This will allow easier post processing of the output and ease comparing output from different extent files.

Example output:

newexit:crucible$ ./target/release/crucible-verify-raw --verbose-csv AEE | head                              
# file:AEE bs:512 bytes  bc:131072  dirty:false gen:4 flush_number:37009748 ext_ver:2 bonus_sync:10766 defrag
:828                                                                                                         
file,block,status,slot_a_result,slot_a_selected,slot_a_flush_id,slot_b_result,slot_b_selected,slot_b_flush_id
,all_zeros                                                                                                   
AEE,0,ok,HashMatch,false,32876,HashMatch,true,53507,false                                                    
AEE,1,ok,HashMatch,false,32876,HashMatch,true,53507,false                                                    
AEE,2,ok,HashMatch,false,32876,HashMatch,true,53507,false                                                    
AEE,3,ok,HashMatch,false,32876,HashMatch,true,53507,false                                                    
AEE,4,ok,HashMatch,false,32876,HashMatch,true,53507,false                                                    
AEE,5,ok,HashMatch,false,32876,HashMatch,true,53507,false                                                    
AEE,6,ok,HashMatch,false,32876,HashMatch,true,53507,false                                                    
AEE,7,ok,HashMatch,false,32876,HashMatch,true,53507,false              

I'm building some other tools to compare output from crucible-verify-raw, but moving to csv first will make that whole process easier.