ioutil's contents are now in io and os.
Eventually jfa-go's files will be embedded in the binary with go1.16's
new embed feature. Using io/fs will provide abstraction for accessing
these files, and allow for both embedded and non-embedded versions.
Also, internal paths to things like email templates, etc. will be
prefixed with "jfa-go:" to indicate to use the app's own Filesystem
instead of reading the file normally. This also allows for custom files
to continue to be used as they are currently.
If two emails fired off at once, they would previously replace each
other's content and possibly send the wrong email to the wrong person.
construct* methods now return the email content, which is sent
separately.
Harvey Tindall