std: Replace num::IntConvertible with {To,From}Primitive
syntax: Add #[deriving(FromPrimitive)] syntax extension

Right now this only works for c-style enums.
syntax: swap from .span_fatal to .span_err in #[deriving(FromPrimitive)]
test: add compile-fail test for #[deriving(FromPrimitive)]
std: Swap {To,From}Primitive to use the 64bit as the unimplemented version

One downside with this current implementation is that since BigInt's
default is now 64 bit, we can convert larger BigInt's to a primitive,
however the current implementation on 32 bit architectures does not
take advantage of this fact.
extra: Add ToBigInt and ToBigUint traits
Package system runtime dependencies into snapshots
Package system runtime dependencies into Windows distribution.
rustdoc: Document what's going on throughout

This addresses some of @huonw's in #9691 about the startling lack of
documentation guiding one throughout the innards of rustdoc::html
auto merge of #9704 : alexcrichton/rust/rustdoc-comments, r=huonw

This addresses some of @huonw's in #9691 about the startling lack of
documentation guiding one throughout the innards of rustdoc::html

r? @huonw
auto merge of #9662 : vadimcn/rust/package-runtime-deps, r=brson

This will make sure that system files that rust binaries depend on in Windows get packaged into stage0 snapshots as well as into Windows installer.
Currently these include `libgcc_s_dw2-1.dll`, `libstdc++-6.dll` and `libpthread-2.dll`.   Note that the latter will need to be changed to `pthreadGC2.dll` once Windows build bots get upgraded to mingw 4.0

Closes #9252
Closes #5878
Closes #9218
Closes #5712
fix some examples in std::rand::Rng
rustc: Use static strings in a few literals

Avoid allocating extra copies of strings by using "" instead of ~"" for
the debug options list and for the `time` function. This is a small
change, but it is in a path that's always executed.
auto merge of #9715 : flo-l/rust/doc-fixes, r=alexcrichton
Register new snapshots

Now that #9662 is merged, we should be much more easily bootstrappable on
windows now.
auto merge of #9717 : blake2-ppc/rust/rustc-static-str, r=alexcrichton

rustc: Use static strings in a few literals

Avoid allocating extra copies of strings by using "" instead of ~"" for
the debug options list and for the `time` function. This is a small
change, but it is in a path that's always executed.
Avoid cloning the stack on every `push_ctxt` call in trans

Rewrite the use of TLS variable for `push_ctxt` so that it uses a ~[]
instead of a @~[]. Before it cloned the whole vector on each push and
pop, which is unnecessary.
auto merge of #9723 : blake2-ppc/rust/trans-no-push-ctxt-clone, r=alexcrichton

Avoid cloning the stack on every `push_ctxt` call in trans

Rewrite the use of TLS variable for `push_ctxt` so that it uses a ~[]
instead of a @~[]. Before it cloned the whole vector on each push and
pop, which is unnecessary.
Cache more results of const_eval

According to http://huonw.github.io/isrustfastyet/mem/#012f909, the "const
marking" pass generates about 400MB of extra memory during compilation. It
appears that this is due to two different factors:

    1. There is a `ccache` map in the ty::ctxt which is only ever used in this
       pass, so this commit moves the map out of the ty::ctxt struct and into
       just this pass's visitor. This turned out to not benefit that much in
       memory (as indicated by http://i.imgur.com/Eo4iOzK.png), but it's helpful
       to do nonetheless.

    2. During const_eval, there are a lot of lookups into decoding inlined items
       from external crates. There is no caching involved here, so the same
       static or variant could be re-translated many times. After adding
       separate caches for variants and statics, the memory peak of compiling
       rustc decreased by 200MB (as evident by http://i.imgur.com/ULAUMtq.png)

The culmination of this is basically a slight reorganization of a caching map
for the const_eval pass along with a 200MB decrease in peak memory usage when
compiling librustc.
auto merge of #9718 : alexcrichton/rust/snapshots, r=sanxiyn

Now that #9662 is merged, we should be much more easily bootstrappable on
windows now.