[Kaleidoscope][BuildingAJIT] Finish off Chapter 1.
[Kaleidoscope][BuildingAJIT] Finish off Chapter 1.

* Various tidy-up and streamlining of existing discussion.
* Describes findSymbol and removeModule.

Chapter 1 is now rough but essentially complete in terms of content.

Feedback, patches etc. very welcome.



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@271225 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm