This includes one breaking change: the default Content-Type of templates
without an identifying extension is now 'Text'. This is to prevent Tera
templates from rendering as HTML without being escaped.
Resolves#1637.
...because loading up a Rocket while it's ignited is a bad idea.
More seriously, because 'Rocket.ignite()' will become an "execute
everything up to here" method.
The new examples directory...
* Contains a `README.md` explaining each example.
* Consolidates examples into more complete chunks.
* Is just better.
Resolves#1447.