thread.h: add atomic_exchange for int and long long
oiiotool --wildcardoff / --wildcardon turn off and on numeric wildcard
expansion for subsequent command line arguments. You can have multiple
on/off commands sprinkled among the arguments. The purpose is to be able
to specify command line arguments with wildcard characters that are NOT
expanded, for example if you are seeing a metadata attribute to contain
an email address (whose '@' would ordinarily be recognized as a numeric
wildcard).