add readme for using embedding crate

src/components/embedding/README.md

@@ -0,0 +1,12 @@
+How to test:
+
+1. Go to http://cefbuilds.com/ and download a binary for your OS/arch
+2. Unpack the (huge) archive
+3. Create both Debug and Release build types for CEF (```./build.sh [Debug|Release]```)
+4. Build servo
+5. Run a CEF-based executable with the embedding crate preloaded:
+	* Linux: ```LD_LIBRARY_PATH=/path/to/cef-bin-unpack-dir/out/$build_type LD_PRELOAD=/path/to/servo/build/libembedding-*.so [CEF EXE]```
+6. Enjoy CEF-powered crashes
+
+Notes:
+* Running with the Debug build in GDB is EXTREMELY slow on startup. Only use this if you are actively debugging an unimplemented CEF interaction.