doc: remove node.js dependency

`prep.js` outputs its own HTML directives, which `pandoc` cannot
recognize when converting the document into LaTeX (this is why the
PDF docs have never been highlighted as of now).

Note that if we were to add the `.rust` class to snippets, we could
probably use pandoc's native highlighting capatibilities i.e. Kate.
fix shootout-spectralnorm, broken since Arc cannot unwrap.
borrowck: classify expressions as assignees, uses or both

- Repurposes `MoveData.assignee_ids` to mean only `=` but not `+=`, so
  that borrowck effectively classifies all expressions into assignees,
  uses or both.
- Removes two `span_err` in liveness analysis, which are now borrowck's
  responsibilities.

Closes #12527.
doc: have a real switch b/w LaTeX compilers
doc: CSS fixes

- fixup and refactor highlighting code
- have a proper print stylesheet
syntax: fixed ICEs and incorrect line nums when reporting Spans at the end of the file.

CodeMap.span_to_* perform a lookup of a BytePos(sp.hi), which lands into the next filemap if the last byte of range denoted by Span is also the last byte of the filemap, which results in ICEs or incorrect error reports.

    Example:
        ````

        pub fn main() {
            let mut num = 3;
            let refe = &mut num;
            *refe = 5;
            println!("{}", num);
        }````

(note the empty line in the beginning and the absence of newline at the end)

The above would have caused ICE when trying to report where "refe" borrow ends.
The above without an empty line in the beginning would have reported borrow end to be the first line.

Most probably, this is also responsible for (at least some occurrences of) issue #8256.

The issue is fixed by always adding a newline at the end of non-empty filemaps in case there isn't a new line there already.
libstd: Change `slice_shift_char`, `shift_char`, `pop_char`, `shift_byte` and `pop_byte` to return an Option instead of failing
libstd: Add unit tests for `slice_shift_char`
libstd: Update docs for `slice_shift_char` and {shift,pop}_{char,byte}
fs: use an iterative algorithm for 'mkdir_recursive'

as requested in #6109
fs: use an iterative algorithm for 'rmdir_recursive'

For now, the windows version uses stat, just as before.
We should switch back to lstat as soon as #12795 is closed.
fs: units tests for mkdir_recusive and rmdir_recursive

The rmdir test is blocked by #12795 on windows.
auto merge of #12670 : dmski/rust/master, r=nick29581

CodeMap.span_to_* perform a lookup of a BytePos(sp.hi), which lands into the next filemap if the last byte of range denoted by Span is also the last byte of the filemap, which results in ICEs or incorrect error reports.

        Example:
            ````

            pub fn main() {
                let mut num = 3;
                let refe = &mut num;
                *refe = 5;
                println!("{}", num);
            }````

(note the empty line in the beginning and the absence of newline at the end)

The above would have caused ICE when trying to report where "refe" borrow ends.
The above without an empty line in the beginning would have reported borrow end to be the first line.

Most probably, this is also responsible for (at least some occurrences of) issue #8256.

The issue is fixed by always adding a newline at the end of non-empty filemaps in case there isn't a new line there already.
auto merge of #12733 : edwardw/rust/rw-liveness, r=nikomatsakis

- Repurposes `MoveData.assignee_ids` to mean only `=` but not `+=`, so
  that borrowck effectively classifies all expressions into assignees,
  uses or both.
- Removes two `span_err` in liveness analysis, which are now borrowck's
  responsibilities.
    
Closes #12527.
Implement hexadecimal floating point literals via a syntax extension

closes #1433
auto merge of #12652 : rcxdude/rust/hexfloatext, r=alexcrichton

Closes #1433. Implemented after suggestion by @cmr in #12323

This is slightly less flexible than the implementation in #12323 (binary and octal floats aren't supported, nor are underscores in the literal), but is cleaner in that it doesn't modify the core grammar, or require odd syntax for the number itself. The missing features could be added back with relatively little effort (the main awkwardness is parsing the string. Is there a good approach for this in the stdlib currently?)
auto merge of #12766 : TeXitoi/rust/fix-shootout-spectralnorm, r=alexcrichton
auto merge of #12793 : brson/rust/installer, r=alexcrichton

Work towards #9876.

Several minor things here:
  * Fix the `need_ok` function in `configure`
  * Install man pages with non-executable permissions
  * Use the correct directory for man pages when installing (this was a recent regression)
  * Put all distributables in a new `dist/` directory in the build directory (there are soon to be significantly more of these)

Finally, this also creates a new, more precise way to install and uninstall Rust's files, the `install.sh` script, and creates a build target (currently `dist-tar-bins`) that creates a binary tarball containing all the installable files, boilerplate and license docs, and `install.sh`.

This binary tarball is the lowest-common denominator way to install Rust on Unix. We'll use it as the default installer on Linux (OS X will use .pkg).

## How `install.sh` works

* First, the makefiles (`prepare.mk` and `dist.mk`) put all the stuff that needs to be installed in a new directory in `dist/`.
* Then it puts `install.sh` in that same directory and a list of all the files to install at `rustlib/manifest`.
* Then the directory can be packaged and distributed.
* When `install.sh` runs it does some sanity checking then copies everything in the manifest to the install prefix, then copies the manifest as well.
* When `install.sh` runs again in the future it first looks for the existing manifest at the install prefix, and if it exists deletes everything in it. This is how the core distribution is upgraded - cargo is responsible for the rest.
* `install.sh --uninstall` will uninstall Rust

## Future work:

  * Modify `install.sh` to accept `--man-dir` etc
  * Rewrite `install.mk` to delegate to `install.sh`
  * Investigate how `install.sh` does or doesn't work with .pkg on Mac
  * Modify `dist.mk` to create `.pkg` files for all hosts
  * Possibly use [makeself](http://www.megastep.org/makeself/) to create self-extracting installers
  * Modify dist-snap bots run on mac as well, uploading binary tarballs and .pkg files for the four combos of linux, mac, x86, and x86_64.
  * Adjust build system to be able to augment versions with '-nightly'
  * Adjust build system to name dist artifacts without version numbers e.g. `rust-nightly-...pkg`. This is so we don't leave a huge trail of old nightly binaries on S3 - they just get overwritten.
  * Create new dist-nightly builder
  * Give the build master a new cron job to push to dist-nightly every night
  * Add docs to distributables
  * Update README.md to reflect the new reality
  * Modernize the website to promote new installers
Add an ItemModifier syntax extension type

Where ItemDecorator creates new items given a single item, ItemModifier
alters the tagged item in place. The expansion rules for this are a bit
weird, but I think are the most reasonable option available.

When an item is expanded, all ItemModifier attributes are stripped from
it and the item is folded through all ItemModifiers. At that point, the
process repeats until there are no ItemModifiers in the new item.
auto merge of #12617 : sfackler/rust/item-modifier, r=alexcrichton

Where ItemDecorator creates new items given a single item, ItemModifier
alters the tagged item in place. The expansion rules for this are a bit
weird, but I think are the most reasonable option available.

When an item is expanded, all ItemModifier attributes are stripped from
it and the item is folded through all ItemModifiers. At that point, the
process repeats until there are no ItemModifiers in the new item.

cc @huonw