gnutls: Revert license to LGPLv2Plus

Since version 3.1.10, gnutls has reverted to the lgpl v2. So
let's mention that.
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.

https://bugzilla.gnome.org/show_bug.cgi?id=740065
libnice.recipe: Fix RAND_bytes symbol collision with openssl

Patch taken from upstream
commands/wipe: Add an option to keep the downloaded sources during wipe
recipes/custom.py: Add FIXME about moving .la static plugin files
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
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
openssl.recipe: Fix libdir, install libtool file, etc

* libdir is /lib even on linux_x86-64, not /lib64 as the build system guesses.
* Install a libtool file, as needed by Cerbero.
* Remove useless RAND_bytes redefinition. This problem was fixed in libnice.

https://bugzilla.gnome.org/show_bug.cgi?id=740084
libsrtp.recipe: Install a libtool file as well

https://bugzilla.gnome.org/show_bug.cgi?id=740084
openh264.recipe: Install a versioned shared lib, and a libtool file

https://bugzilla.gnome.org/show_bug.cgi?id=740084
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