automated whitespace fixes
update the libstd docstring for the rename
Revert "Revert "Remove all usage of the global LLVMContextRef""

This reverts commit 541c657a738006d78171aa261125a6a46f283b35.
Revert "Revert "Have JIT execution take ownership of the LLVMContextRef""

This reverts commit 19adece68b00bd1873499cca6f1537750608d769.
Correctly parse commands for rusti

Closes #7120
Don't run passes again on JIT code

These passes are already run beforehand, no need to do them twice.
Resolve LLVM crashing in rustpkg tests
auto merge of #7116 : thestinger/rust/whitespace, r=luqmana
Add caches for method and impl metadata

The lookups for these items in external crates currently cause repeated
decoding of the EBML metadata, which is pretty slow. Adding caches to
avoid the repeated decoding reduces the time required for the type
checking of librustc by about 25%.
add IteratorUtil to the prelude
rm ExtendedMutableIter

replaced with `xs.mut_iter().enumerate()`
rm MutableIter

replaced with mutable implementations of Iterator
rm CopyableNonstrictIter

copies can just be done explicitly: `xs.transform(|x|x.clone())`
auto merge of #7144 : dotdash/rust/caches, r=graydon

The lookups for these items in external crates currently cause repeated
decoding of the EBML metadata, which is pretty slow. Adding caches to
avoid the repeated decoding reduces the time required for the type
checking of librustc by about 25%.
auto merge of #7110 : thestinger/rust/iterator, r=brson
auto merge of #7121 : huonw/rust/rand-call, r=pnkfelix

r? @pnkfelix
auto merge of #7122 : thestinger/rust/std, r=luqmana
auto merge of #7125 : alexcrichton/rust/rusti-issues, r=brson

This un-reverts the reverts of the rusti commits made awhile back. These were reverted for an LLVM failure in rustpkg. I believe that this is not a problem with these commits, but rather that rustc is being used in parallel for rustpkg tests (in-process). This is not working yet (almost! see #7011), so I serialized all the tests to run one after another.

@brson, I'm mainly just guessing as to the cause of the LLVM failures in rustpkg tests. I'm confident that running tests in parallel is more likely to be the problem than those commits I made.

Additionally, this fixes two recently reported issues with rusti.
std: convert str::{map,levdistance,subslice_offset} to methods.

The first two become map_chars and lev_distance. Also, remove a few
allocations in rustdoc.
std: convert str::to_utf16 to a method.