Drop the underactuated textbook from Drake (RobotLocomotion#6889)

* drop the underactuated textbook from Drake

Russ has indicated that he will work the other way around if necessary, i.e. pull in Drake.

* cleanup cmake around the textbook

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "drake/doc/textbook"]
-	path = drake/doc/textbook
-	url = https://github.com/RussTedrake/underactuated.git
 [submodule "externals/googletest"]
 	path = externals/googletest
 	url = https://github.com/google/googletest.git

CMakeLists.txt

@@ -122,12 +122,6 @@ drake_add_external(pythonqt CMAKE PYTHON QT
     -DPythonQt_Wrap_Qtuitools:BOOL=ON
 )
 
-# textbook
-drake_add_external(textbook PUBLIC CMAKE MATLAB PYTHON
-  CMAKE_ARGS -DBUILD_TESTING=${Matlab_FOUND}
-  INSTALL_COMMAND :
-  SOURCE_DIR ${PROJECT_SOURCE_DIR}/drake/doc/textbook)
-
 # tinyobjloader
 drake_add_external(tinyobjloader PUBLIC CMAKE
   CMAKE_ARGS
@@ -199,7 +193,6 @@ drake_add_external(drake LOCAL PUBLIC CMAKE ALWAYS MATLAB PYTHON VTK
     -DWITH_PYBIND11:BOOL=${WITH_PYBIND11}
     -DWITH_PYTHON_3:BOOL=${WITH_PYTHON_3}
     -DWITH_SPDLOG:BOOL=${WITH_SPDLOG}
-    -DWITH_TEXTBOOK:BOOL=${WITH_TEXTBOOK}
     -DWITH_TINYOBJLOADER:BOOL=${WITH_TINYOBJLOADER}
     -DWITH_YAML_CPP:BOOL=${WITH_YAML_CPP}
   DEPENDS
@@ -218,7 +211,6 @@ drake_add_external(drake LOCAL PUBLIC CMAKE ALWAYS MATLAB PYTHON VTK
     pybind11
     robotlocomotion_lcmtypes
     spdlog
-    textbook
     tinyobjloader
     yaml_cpp
 )

cmake/options.cmake

@@ -297,9 +297,6 @@ macro(drake_setup_options)
   #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   # BEGIN external projects that are OFF by default
 
-  drake_optional_external(TEXTBOOK OFF
-    "The Underactuated Robotics textbook and its examples")
-
   # END external projects that are OFF by default
   #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   # BEGIN indirectly optional external projects

drake/CMakeLists.txt

@@ -144,8 +144,4 @@ if(ENABLE_DOCUMENTATION)
   add_subdirectory(doc)
 endif()
 
-if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/doc/textbook/CMakeLists.txt)
-  add_subdirectory(doc/textbook)
-endif()
-
 drake_install_cmake_package_config_files()