Consolidated update to Squirrel (#749)

* Build Sparkle from source

* Automate codesign

* update rime icon for macOS 13

* address deprecated methods

* All UI Changes

* Update project.pbxproj

* Handle abbrev status label update

* Adopt TextKit 2

* Update readme and compilation guide

* Optimize right corners

* Select by clicking

* Bug fix and code optimization

Fix a bug, that utf8len returns length in UTF32, instead of UTF16, which is used in NSString.

Further reduce chances of artifacts appearing

refactor code

* Better mouse event handling

* Update to new change page API

* revert change in README

Author: LEOYoon-Tsaw

.gitignore

@@ -4,6 +4,7 @@ Squirrel.xcodeproj/project.xcworkspace/
 Squirrel.xcodeproj/xcuserdata/
 build/
 build.log
+Frameworks/*
 bin/*
 lib/*
 data/opencc/

.gitmodules

@@ -5,3 +5,6 @@
 [submodule "plum"]
 	path = plum
 	url = https://github.com/rime/plum.git
+[submodule "Sparkle"]
+	path = Sparkle
+	url = https://github.com/sparkle-project/Sparkle

Assets.xcassets/RimeIcon.appiconset/Contents.json

@@ -1,13 +1,13 @@
 {
   "images" : [
     {
-      "filename" : "rime-small-16.png",
+      "filename" : "rime-16 1.png",
       "idiom" : "mac",
       "scale" : "1x",
       "size" : "16x16"
     },
     {
-      "filename" : "rime-small-32.png",
+      "filename" : "rime-32 1.png",
       "idiom" : "mac",
       "scale" : "2x",
       "size" : "16x16"