gobject-introspection.recipe: Move to build-tools, and add to bootstrap

This allows us to build g-i support on platforms other than Linux as well
gobject-introspection.recipe: Generate URL from components, remove useless autoreconf
New recipe: icu.recipe
harfbuzz.recipe: Now that we have ICU, we can actually build with ICU support
New recipe: libsusrsctp.recipe
New recipe: gnome-js-common.recipe
New recipe: javascriptcoregtk.recipe

Lots of hacks to build only JSC and not WebKit-GTK+
More hacks to cross-compile on Android
New recipe: seed.recipe
android: Add an android-sdk recipe and add it to the bootstrap
custom.py: Add a function to convert .gir to .gir.h

This is used by openwebrtc-girepository and openwebrtc
New recipe: openwebrtc-girepository.recipe
New recipe: openwebrtc-gst-plugins.recipe
New recipe: openwebrtc.recipe
openwebrtc.recipe: Build JNI bindings on Android

openwebrtc.jar and openwebrtc_bridge.jar are installed in PREFIX/lib/jni
gnome-common: New recipe
build-tools: Add gnome-common to bootstrap
seed: Use system javascriptcore for OSX/iOS and depend on g-i for OSX
seed: Also use JavaScriptCore in the pkg-config file for OSX/iOS
seed: Remove patches that are in seed git master already
seed: Use a specific git commit and mention that in the recipe version too