Specs: Split apis.md into dom.md, events.md, idl.md, and move the remainder into README.md and modu…

sky/specs/README.md

 The Sky Environment
 ===================
 
 The main files loaded by the Sky environment are Sky files, though
 they can refer to binary resources like images and fonts.
 
 Sky files
 ---------
 
 Conventional MIME type: ``text/sky``, though this type is neither
 necessary nor sufficient to indicate that a file is a Sky file; only
 the signature matters for type dispatch of Sky files.
 
 Conventional extension: ``.sky``
 
 Signatures:
 
 For application files, one of the following:
 * ``23 21 6d 6f 6a 6f 20 6d 6f 6a 6f 3a 73 6b 79 0a`` ("``#!mojo mojo:sky\n``")
 * ``23 21 6d 6f 6a 6f 20 6d 6f 6a 6f 3a 73 6b 79 0d`` ("``#!mojo mojo:sky\r``")
 * ``23 21 6d 6f 6a 6f 20 6d 6f 6a 6f 3a 73 6b 79 20`` ("``#!mojo mojo:sky ``")
 
 For module files, one of the following:
 * ``53 4b 59 20 4d 4f 44 55 4c 45 0a`` ("``SKY MODULE\n``")
 * ``53 4b 59 20 4d 4f 44 55 4c 45 0d`` ("``SKY MODULE\r``")
 * ``53 4b 59 20 4d 4f 44 55 4c 45 20`` ("``SKY MODULE ``")
+
+
+Notes
+-----
+
+```
+magical imports:
+  the core mojo fabric JS API   sky:mojo:fabric:core
+  the asyncWait/cancelWait mojo fabric JS API (interface to IPC thread)  sky:mojo:fabric:ipc
+  the mojom for the shell, proxying through C++ so that the shell pipe isn't exposed  sky:mojo:shell
+  the sky API  sky:core
+  the sky debug symbols for private APIs  sky:debug
+```