envOrOption: Grab either env variable or option
Description
.Rprofile options are like "crunch.api", while env vars are "R_CRUNCH_API".
This function will use the environment variable if it is found, otherwise
it looks for the R-based option value.
Usage
envOrOption(opt, default = NULL)
Arguments
default
if the specified option is not set in either the option or as
an environment variable, use this instead.
Value
the value of the option