Delete `Number.toInteger` test

`Number.toInteger` was removed from the ES6 draft. Fixes #62.

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

sth: correct syntax error in new fn isAsyncTest

test262.py: only include helper scripts when needed

CONTRIBUTING: document test262.py, async tests

add a section on requirements for using console test runner test262.py

add a section on asynchronous tests

add subsection to authoring guidelines with suggestion for test names

test262.py: only supply async helper scripts when test is async
sth.js: factor out function isAsyncTest()
timer.js: improve workaround for async tests when Promise is defined but setTimeout is noot

timer.js emulates setTimeout using Promise by doing a busy loop that checks
if `timeout` milliseconds have elapsed.  Modified check to (timeLeft > 0) instead
of (!timeLeft) to prevent infinite loop when check does not happen to run
at precise millisecond timeout expires.

Because test262.py did not support the $INCLUDE directive, some helper
scripts were added to every test -- notably testIntl, timer, and donePrintHandle
Now that $INCLUDE is supported, these can be dropped, speeding overall test run time

* hankyates/array-fill-tests:
  Adding Array.prototype#fill tests

Propagate error code when test cases are failed

Initial promise tests

packager: make packager runnable

packager.py cannot run due to syntax errors in a few script files

packagerConfig: use git instead of hg
test262: use pop instead of delete to avoid throw if property missing
S22.1.2.1_T*: fix docString header comment: s/b /**
S22.1.2.1_T3: fix docString header comment: s/b /**, fix end of docstring * / => */

doneprintHandle.js: make $DONE accept any falsy argument as meaning 'pass'
PromiseHelper.js: checkSequence: new helper fn for async tests
.gitignore: port .hgignore to .gitignore syntax
test262.py: support $INCLUDE directive in python test runner

S25.4.4.1*: tests to cover Section 25.4.4.1, Promise.all( iterable )
A1.1: Promise.all is callable
A1.2: Promise.all expects 1 argument
A2.1: Promise.all([]) is a Promise
A2.2: Promise.all([]) is resolved immediately
A2.3: Promise.all([]) is resolved with a new empty array
A3.1: Promise.all expects an iterable argument

* mgmeyers/Array.prototype.find:
  Adds tests for Array.prototype.find

* es6Tests:
  first batch of ES6 tests

* hankyates/array-of-tests:
  Adding Array#of tests

* array-from-tests:
  Adding test for Array.from

* tdahlstrom/bug_596:
  Bug 596 - Coverage: 15.4.4.11 - identical elements and array holes

Adding Support for Async Tests

15.5.4.9_CE should check for locale-sensitive comparison

Add contributing.md and update readme.md

change test 15.3.5.4_2-89 to call bound function before returning (Fixes bugzilla 1533)

fix error msgs in test S12.6.1_A1 from Bugzilla issue 1561

change assert to not assume a sorted list of arguments indices (Fixes bugzilla 1159)

fix point of view typos from Bugzilla 1552

fix typo in 10.5 (fixes Bugzilla 1795)