Changes to way makemap handles control-C interupts

There have been some changes to the way that makemap behaves when control-C is pressed (or a SIGINT signal is received by the process by any other means). When the first control-C is detected, makemap will continue to complete the current iteration (but a second interupt will cause makemap to terminate immediately). It will then pause and ask the user what to do next. The options are:

1. abort immediately with an error status
2. close the application returning the current output map
3. do one more iteration to finialise the map and then close

Option 3 is important if you are using AST masking, since one final iteration should always be done without masking to ensure correct fluxes in the background regions (see the AST.ZERO_NOTLAST config parameter). If you are not using AST masking, or if you will be re-starting makemap to perform further iterations, then you should select option 2.

At some point I will add a fourth option to ignore the interupt and continue iterating to convergence.

Note if you are running makemap from within a script, then the handling of control-C interupts will probably be quite different, because the shell (or perl, python or whatever) will catch the interupt before it gets to makemap. You may get some sort of useful behaviour by finding the process ID for the makemap process itself, and sending a SIGINT to that process explicitly:

% ps aux | grep makemap

dsb      25407  0.0  0.0  43716  1952 pts/5    S    Jul03   0:00 makemap

% kill -s INT 25407