Update README.md

README.md

-This contains some scripts to add metadata to the camras pulsar format, i.e. the format that comes out of `pulsar_record`.
+```
+./tofil.py --help
+usage: tofil.py [-h] [-i INFILE] [-o OUTFILE] [-d DATE] [-s SOURCE]
+                [--skip-header]
+
+Convert a camras pulsar file (output of pulsar_record) to filterbank format
+
+optional arguments:
+  -h, --help            show this help message and exit
+  -i INFILE, --infile INFILE
+                        Input CAMRAS pulsar file. If empty, create just the
+                        header.
+  -o OUTFILE, --outfile OUTFILE
+                        Name of output file, e.g. 'B0329.fil' (default:
+                        guessed from input filename)
+  -d DATE, --date DATE  Start date/time of observation, in 'isot' format
+                        (defaults to creation date of file, or now if no
+                        infile given)
+  -s SOURCE, --source SOURCE
+                        Name of the source, e.g. 'PSR B0329+54' (default:
+                        guessed from input filename)
+```
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