Split CORE and ANNEX:

Squashed commit of the following:

commit 61db73abaf329035bb74c87e8c90b026dd991dda
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 12:54:08 2013 +0900

    Update Changes.txt

commit 8ed7ae732a9935172aef9a475463d8aab0c9ca7e
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 12:49:52 2013 +0900

    Fix wording of Annex's note.

commit bcaa507cfaf6b5b92bd09d635d52c31785ba2d9e
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 12:49:37 2013 +0900

    Add a note for 'locale'

commit ba7d02704c12fd4f5c0d29ba3c3ca362e8c2919b
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 12:49:06 2013 +0900

    Remove 'IME reference' background section in Annex.

commit 020513cf9159656d6446312d5ea562d8c7cbc778
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 12:48:39 2013 +0900

    Fix reference to 'locale' and 'composition' in Overview.html

commit 9aeb1555b7c7ce3820ab25405257281a617d34d2
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 12:27:22 2013 +0900

    Remove setCaretRectangle/{enable,disable}EditingEvents

commit 5a2f203cebf785fdd36fd7ace9084de76881d455
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 11:42:20 2013 +0900

    Add a note about the status of this document.

commit e04568f86d4e2248669e5531f380763af53e5b19
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 11:41:47 2013 +0900

    Cut off CompositionEvent and rewrite documentation.

commit 69dd23fd9d940dcaf08882e77d94ee5a53048053
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 11:34:47 2013 +0900

    Rename Overview2 to Annex.

commit 28b6512674bf7729f88974ed10dd541fae48828c
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 11:24:36 2013 +0900

    Duplicate the document:
      Overview.html for primary IME API (UI events)
      Overview2.html for secondary IME API (Composition)

commit f4a0d53d985fa07d6fe5936382ec481c47a801ff
Author: Takayoshi Kochi <kochi@chromium.org>
Date:   Mon Dec 2 11:22:41 2013 +0900

    Update Changes.txt for include CompositionEvent change.