84202472 turn off input echo by default

Addresses issue #4589  

Since this is trying to minimize the writing to the audit file, it could not depend on a input in the IDF file so instead it is using environmental variable called "DisplayInputInAudit" that shows the input file in the audit file only when set to Yes. 
Nit picking here, but these two lines need spaces inside the parens.  There are a bunch of settings in VS that can help automate this formatting.