PATCH: Backport from v22.

Compiles on 32-bit non-JIT enabled platforms.

Original patch:
https://hg.mozilla.org/mozilla-central/rev/489ab986ea69

Discussion:
https://bugzilla.mozilla.org/show_bug.cgi?id=846986
build.sh for iOS

Simulator first, then device
Adds README.md
Update README.md

updates info for Android and win32
fix of android build with ndk-r8e. And enable JIT support for android.
Enable JIT support for win32.
Merge pull request #18 from dumganhar/spidermonkey21-fix

fix of android build with ndk-r8e. And enable JIT support for android and win32.