Eliminate most std:: imports
Build with #![no_std]
Ditch std::ascii

When it moves into core and/or collections, we can drop some of this code.

See rust-lang/rust#16801.
Switch from HashMap to TreeMap for tokenizer profiling

Because HashMap requires libstd and a task-local RNG (by default).
Allow building the library without libstd at all
Implement a C API for the tokenizer
Don't use NULL values for extern "C" fn in the C API
Switch to string-cache for string interning
Upgrade to rustc 0.12.0-pre (0bdac78da 2014-09-01 21:31:00 +0000)
Use my string-cache fork temporarily
Remove workaround for rust-lang/rust#16643
Update html5lib-tests
Replace Namespace with Atom

Fixes #26.
Replace Str-generic method with a new trait

See rust-lang/rust#16738.
Test-build the C API on Travis
Fix string-cache revspec for Travis