proposed change for iMesh & iGeom options strings

[Jason Kraftcheck]

Hi all,

I'd like to propose a minor change to API for those functions that accept
options strings (a behavioral change w/out changing any declarations in the
headers).  Our current options string format is a list of string options
each preceded by a separator character, such that the user's choice of
separator character can be determined from the first character of the
options string.  For example:
  ;FOO=BAR;FORMAT=BINARY
or
  *FOO=BAR*FORMAT=BINARY

However, this format can be a little bit error prone when passing only one
option, as it is easy to forget to specify the separator character.  For
example:
  ;FOO=BAR
vs
  FOO=BAR

I'm proposing that we make it an error to specify an alphanumeric (a-z, A-Z,
0-9) character as the separator.  This seems very likely to result in an
error when the leading separator is forgotten and is unlikely to break any
existing code (I doubt anyone would actually want to use an alphanumeric
character for the separator.)

- jason