Handle divide by zero in constant evaluator
doc: Document mutable function arguments
core: Rename to_mut and from_mut to cast_to_mut and cast_from_mut
doc: Document pattern matching on vectors
Merge pull request #4588 from sanxiyn/doc-mut-arg

doc: Document mutable function arguments
Merge pull request #4596 from Trinick/tomutrename

core: Rename to_mut and from_mut to cast_to_mut and cast_from_mut
Add Bill Fallon to AUTHORS
libsyntax: Implement the `+` syntax for multiple trait bounds. r=tjc
rename send_map to hashmap

This makes the module much more discoverable, and is in line with the
'treemap' naming.
get rid of the std::map::Map LinearMap impl

This legacy trait needs to be dropped in order to migrate to
core::container::Map, which doesn't require @ and Copy, and will make
proper use of borrowed pointers.
rename hashmap find/get -> find_copy/get_copy
rename hashmap find_ref/get_ref -> find/get
add find method to the core::container::Map trait
remove the LinearMap get_copy method

This isn't simpler (or faster) than just doing the copy in the caller,
and it doesn't work for types that can be cloned but not copied.
libcore: Use LLVM intrinsics for floor; add a new Perlin noise benchmark. r=brson
renaming to adhere to conventions
remove cautionary wording in the hashmap docstring

it's pretty solid, at least relative to most of the other modules
Long lines
rm unnecessary usage of 'unsafe' from hashmap
improve hashmap/treemap documentation