turn std::oldmap into a wrapper around LinearMap
core: derive Clone for core types
replace impls with `deriving` where applicable
make crates with the same name sort consistently
librustc: emit loop for expr_repeat instead of 2n instructions in [x, ..n]
Kill some warnings: unused imports and old #[deny(..)]s.
libcore: implement `str::each_char_reverse` correctly.

Previously, `each_char_reverse` was not iterating at all, so the
testcase never ran properly.
treemap: add a find_mut method
librustc: clean-up expr_repeat loop generation: use native integers
hashmap: add find_mut method
trie: add find_mut method
smallintmap: add find_mut method
expose find_mut in the Map trait
trie: improve docstring
rustdoc: Show purity
configure: error on unsupported target-triples and arm-linux-androideabi fix
kate: remove `const`, `log`, and `pure` keywords, add `super` keyword
configure: simplify pandoc version recognition.

The version recognition was failing for version 1.11, thinking the
minor version was 1 rather than 11.
core: Fix doc comment error, as per #4983
make ty_region give a useful span when it fails