This is a breaking change.
This commit introduces `RawStr` to forms. In particular, after this
commit, the `&str` type no longer implements `FromFormValue`, and so it
cannot be used as a field in forms. Instad, the `&RawStr` can be used.
The `FormItems` iterator now returns an `(&RawStr, &RawStr)` pair.
This commit changes the way Rocket parses form items. In particular, it now
(liberally) validates form strings, returning a Bad Request on malformed inputs
and Unprocessable Entity on bad parses.
The 'FormItems' iterator was modified to accomodate this. The iterator is now
initialized using 'from': 'FormItems::from(form_string)'. The iterator can be
queried to check for a complete parse using either 'completed()' or
'exhausted()', the latter of which will consume valid keys/values and return
true only if the entire string was consumed.
The 'FromForm' trait now takes a mutable borrow to a 'FormItems' iterator.
The 'Form' and 'FormForm' implementation for 'Form' were modified to use the new
iterfaces and check for 'exhausted' after a parse, returning a Bad Request error
if the iterator cannot be exhausted.
Resolves#46.
* All From* trait methods are now named like the trait.
* All From* traits have an associated Error type.
* Document all of the `form` module.
* Add codegen tests for auto-derived forms.
* The param parsing traits now live under Request.
Sergio Benitez