CONTRIBUTING: add notes on async

add a table showing which print handle to use when
running async tests through test262.py runner

@anba contributed information about async tests in
SpiderMonkey and JavaScriptCore
Merge pull request #53 from smikes/CONTRIBUTING-async-printhandles

CONTRIBUTING: add notes on async
Fix suspect formatting in S15.2.3.1_A3
Delete `Number.toInteger` test

`Number.toInteger` was removed from the ES6 draft. Fixes #62.
Merge pull request #65 from mathiasbynens/patch-1

Delete `Number.toInteger` test
Normalize testcase format

This commit normalizes the test case format used across test262. It applies the following transformations:

* Convert to YAML for frontmatter
* Remove of trailing whitespace
* Replace /r/n with /n except in chapters 6 and 7.
* Copyright header always uses // comments
* new includes attribute replaces $INCLUDE
* No implicit assumptions about test environment other than $ERROR. Everything else appears in the include array. This includes "runTestCase" which is now included in a substantial number of tests.
Add path attribute.
tools, harness: support new YAML frontmatter

parseTestRecord: add support for YAML frontmatter
parseTestRecord: initial unit test for test record parser
parseTestRecord: refactor for testing

factor old parsing; add YAML parsing

runner: support "includes" from YAML frontmatter

support frontmatter "includes" in python runner
use test.includes if present instead of scanning test code with regex

harness: factor individual functions out into files

tools: handle YAML errors

tolerate missing keys in dictionary (flags, includes)
report filename when empty frontmatter block
new option --list-includes to test262.py

harness: factor helper functions into separate files

sth: remove extra close-paren (syntax error)

test_common: TDD; failing parse of YAML

common: use parseTestRecord (YAML-aware)
Merge pull request #51 from bterlson/normalize-format

Normalize testcase format
Merge branch 'master' of https://github.com/tc39/test262