libnice: Disable gtk-doc unconditionally, and disable static by default

gtk-doc support needs the .pc file, which isn't inside Cerbero and causes
a build failure.

Static plugin libraries should only be installed by the -static recipe.
libnice.a is still needed inside libnice.recipe, though.
commands/wipe: Add an option to keep the downloaded sources during wipe
openssl.recipe: Fix libdir

libdir is /lib even on linux_x86-64, not /lib64 as the build system guesses
glib.recipe: fix patch 0001 -- always AC_SUBST

Without this, @COCOA_LIBS@ and @CARBON_LIBS@ remain in Libs.Private in
gio-2.0.pc and glib-2.0.pc
recipes/custom.py: Add FIXME about moving .la static plugin files
libsrtp.recipe: Install a libtool file as well
openssl.recipe: Install a libtool file as well
openh264.recipe: Install a libtool file as well
cerbero/utils/git: Use 'cerbero_build' as the branch for applying patches

'build' is too generic, it's a good idea to use a namespaced branch name
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

Cross-compilation is complicated, so has been left alone for now
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