Add TLS-Support

[julienschmidt]

Fixes #25

Currently with Go 1.0 API in tests until Travis CI supports Go 1.1

[arnehormann]

I didn't spot the changes here. Should be ok :)

[julienschmidt]

The config struct has 2 new fields

[arnehormann]

LGTM for me, but m server doesn't have SSL built in, so I didn't test this. If you tested it, I'm fine with it.
If it's not built into Travis version of MySQL, we should document or detect that somehow so this stays supported and we don't regress by accident because the test is skipped.

[arnehormann]

Thought about it...
We should make the ssl test explicit and never skip it.
If Travis doesn't include ssl enabled Mysql, we'll have to find another way. If it does, we should make sure this test is never skipped, not even when Travis changes the build so we get early warnings.
Maybe we should setup a different repo like "github.com/go-sql-driver/mysql-ssl-status" importing the driver and requiring an ssl connection so we can see if that fails and include the link to the build status here as "ssl status"?

[julienschmidt]

This if case is the only part that could break without being noticed by Travis. I don't think this is worth all the effort. I have 2 test systems with TLS enabled, this should be enough.