Exported by Common, so they will be available everywhere.
These are the same as readFile, writeFile, appendFile.
But have two benefits:
* They take OsPath, so using them avoids converting back and forth
unncessarily.
* They use the close-on-exec flag so can't leak FDs to child processes.
Unlike the standard Haskell versions which unfortunately have that
wart currently. (I do hope the standard versions get fixed
eventually.)
Sponsored-by: the NIH-funded NICEMAN (ReproNim TR&D3) project
