Merge pull request #504 from bocoup/explicit-async

CONTRIBUTING.md

test/built-ins/Promise/S25.4.3.1_A2.3_T1.js

test/built-ins/Promise/S25.4.3.1_A2.4_T1.js

test/built-ins/Promise/S25.4.3.1_A4.1_T1.js

test/built-ins/Promise/S25.4.3.1_A5.1_T1.js

test/built-ins/Promise/S25.4.3.1_A5.1_T2.js

test/built-ins/Promise/all/S25.4.4.1_A2.2_T1.js

test/built-ins/Promise/all/S25.4.4.1_A2.3_T1.js

test/built-ins/Promise/all/S25.4.4.1_A2.3_T2.js

test/built-ins/Promise/all/S25.4.4.1_A2.3_T3.js

test/built-ins/Promise/all/S25.4.4.1_A3.1_T1.js

test/built-ins/Promise/all/S25.4.4.1_A3.1_T2.js

test/built-ins/Promise/all/S25.4.4.1_A3.1_T3.js

test/built-ins/Promise/all/S25.4.4.1_A5.1_T1.js

test/built-ins/Promise/all/S25.4.4.1_A6.1_T2.js

test/built-ins/Promise/all/S25.4.4.1_A7.1_T1.js

test/built-ins/Promise/all/S25.4.4.1_A7.2_T1.js

test/built-ins/Promise/all/S25.4.4.1_A8.1_T1.js

test/built-ins/Promise/all/S25.4.4.1_A8.2_T1.js

test/built-ins/Promise/all/S25.4.4.1_A8.2_T2.js