tabs --> spaces

Also:
- Reformatted some doxygen comments in header files
- Removed unnecessary "This is CMakeLists for..." comments from CMakeLists.txt
  files
- Trimmed down the "Exposed API" in some of the requirements docs to be
  consistent with the others
- Removed an unused variable from broker.h and friends
- Fixed some JSON syntax errors in doc/sample_ble.md

Author: damonbarry

bindings/dotnet/CMakeLists.txt

@@ -4,11 +4,11 @@
 cmake_minimum_required(VERSION 2.8.11)
 
 set(dotnet_sources
-	./src/dotnet.cpp
+    ./src/dotnet.cpp
 )
 
 set(dotnet_headers
-	./inc/dotnet.h
+    ./inc/dotnet.h
 )
 
 include_directories(./inc)