Allow :ca_path or :ca_file to be passed in as settings, for SSL context

[ndbroadbent]

RE: Issue #345

Also refactored SSL context code in Mail::SMTP to use a shared private method: #ssl_context.

[ffa]

I support this pull request. This pull request adds the setting for validating ca certificates. Without this, SSL/TLS may be much more easily spoofed and therefore renders SSL/TLS considerable less secure. Furthermore, the default setting is for ca_path or ca_file to be used.

[mikel]

Hi there, looks like a good idea. Though making the default to require ca_path and ca_file is going to cause a lot of grief. Please change the PR to make current behaviour the default and I'll merge in.

[mikel]

Hi there, just took another look at your pull request, and seems like you are defaulting to using the dummy context requiring the ca stuff by default which is good.... however, we recently merged a pull request in to make SSL work on Ruby 1.8.7 and this now conflicts.

Could you rebase against master?

[jeremy]

Ping! @ndbroadbent up for rebasing?

[ndbroadbent]

Rebased!

[jeremy]

Thanks @ndbroadbent!