Add platform/prebuilts/android-emulator

Change-Id: I5533fc529173b8f3ff2d74f9bce4e04af6d417e2
Update manifest for latest external/chromium_org.

Bring the chromium_org projects in sync with the latest version.

Change-Id: Iffefd8539530b58255153fac40e5b92cefa11312
Add host prebuilts for Clang 3.5.

Change-Id: I2e2a3f921e67e972ef9962257ef80903780a031b
Add missing libcxx-related projects to the manifest.

Change-Id: Ia404060e67e3b5e191dbc5e6f51be74d3bca6f61
Update libcxx and libcxxabi projects
Move to glibc2.11-4.6
Add platform/prebuilts/gcc/linux-x86/host/x86_64-w64-mingw32-4.8