[NUP-2399] Added style guides to new guide

CONTRIBUTING.md

@@ -46,18 +46,18 @@ Provide technical details about how code changes are vetted, tested, approved, a
 
 #### [Release Process](RELEASE.md)
 
-Learn more about how NuPIC is released through the wiki linked above.
+Learn more about how NuPIC is released through the page linked above.
 
 ### Developer Resources
 - [Development Tips](https://discourse.numenta.org/t/development-tips/2140)
-- [C++ Development Workflow](https://github.com/numenta/nupic.core/wiki/Development-Workflow)
+- [Developer Workflow](https://discourse.numenta.org/t/developer-workflow/2132)
 - [Documenting Code](docs/README.md)
 - [External Libraries](https://discourse.numenta.org/t/external-libraries/2141)
-- [Profiling and Optimization for Speed](https://github.com/numenta/nupic/wiki/Optimization-&-Profiling,-Speed)
+- [Profiling and Optimization for Speed](https://discourse.numenta.org/t/optimization-profiling-speed/2142)
 
 #### Coding Standards and Guides
 
-- [C/C++ Coding Guide](https://github.com/numenta/nupic/wiki/C-Coding-Guide)
+- [C/C++ Coding Guide](https://numenta.github.io/nupic/guides/contributing/cpp-style-guide.html)
 - [CMake Style Guide](https://discourse.numenta.org/t/cmake-style-guide/2137/1)
 - [Python Style Guide](https://discourse.numenta.org/t/python-style-guide/2128/1)
 - [Contribution Standards](https://discourse.numenta.org/t/contribution-standards/2130/1)

docs/source/contributing/cmake-style-guide.md

@@ -0,0 +1,47 @@
+# CMake Style Guide
+
+## Naming
+
+**Functions**: _lower_case_ name. Ex:
+`do_something(...)`
+
+**Local variables**: _lower_case_ name. Local variables are used exclusively inside the file that contained them, and their values were simply passed as parameters to CMake functions. Ex:
+`set(some_variable "...")`
+
+**Global variables**: _UPPER_CASE_ name. Global variables(can also be called "export variables") are intended for exporting up/down-stream via the environment variable mechanism. Ex:
+`set(SOME_VARIABLE "...")`
+
+**Control statements**: _lower_case_ name without repeat the condition in the closing brackets. Ex:
+
+```
+if(condition)
+  ...
+else() # not repeat condition
+  ...
+endif() # not repeat condition
+```
+
+**Operators**: _UPPER_CASE_ name. Ex:
+`if(condition STREQUAL "")`
+
+**Directives and/or extra options**:  _UPPER_CASE_ name. Ex:
+`do_something(... USE_THIS)`
+
+## Examples
+
+An real-world example:
+
+```
+function(set_platform system_name)
+  if(${system_name} MATCHES "Darwin")
+    set(PLATFORM "darwin")
+  elseif(${system_name} MATCHES "Linux")
+    set(PLATFORM "linux")
+  else()
+    set(PLATFORM "")
+  endif()
+endfunction()
+
+cmake_minimum_required(VERSION 3.0)
+set_platform(${CMAKE_SYSTEM_NAME})
+```