Move emugl system code to development.git

Because of the way the SDK and Android system images are branched,
host code that goes into the SDK tools can't live in the same
repository as code that goes into the system image. This change keeps
the emugl host code in sdk.git/emulator/opengl while moving the emugl
system code to development.git/tools/emulator/opengl.

A few changes were made beyond simply cloning the directories:

(a) Makefiles were modified to only build the relevant components. Not
    doing so would break the build due to having multiple rule
    definitions.

(b) Protocol spec files were moved from the guest encoder directories
    to the host decoder directories. The decoder must support older
    versions of the protocol, but not newer versions, so it makes
    sense to keep the latest version of the protocol spec with the
    decoder.

(c) Along with that, the encoder is now built from checked in
    generated encoder source rather than directly from the protocol
    spec.  The generated code must be updated manually. This makes it
    possible to freeze the system encoder version without freezing the
    host decoder version, and also makes it very obvious when a
    protocol changes is happening that will require special
    backwards-compatibility support in the decoder/renderer.

(d) Host-only and system-only code were removed from the repository
    where they aren't used.

(e) README and DESIGN documents were updated to reflect this split.

No actual source code was changed due to the above.

Change-Id: I70b576a70ac3dc94155f931508b152178f1e8cd5
86 files changed