Issue #195. Using external project to simplify the maintainence. centos-6 has

cmake 2.8 which is now the minimum version required to build moose.
Revered back Makefile in moose-core.
Update README.md
Fixed indentation.

CMakeLists.txt

 CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
-PROJECT(moose-all)
+
+PROJECT(MOOSE)
 set(MOOSE_VERSION "3.0.2")
+include( ExternalProject )
+
+
+# Options to pass down to moose-core
+option(WITH_DOC "Build documentation" OFF)
+option(DEBUG "Build with DEBUG support" OFF)
+option(WITH_BOOST "Use Boost libraries instead of GSL" OFF)
+option(WITH_CUSA "Use CUDA/GPU" OFF)
+option(WITH_MPI "Use MPI" OFF)
 
 ## intialize paths
 set(MOOSE_CORE_DIR "${CMAKE_SOURCE_DIR}/moose-core")
 set(MOOSE_CORE_BUILD_DIR ${CMAKE_BINARY_DIR}/_build_moose_core)
+set(MOOSE_CORE_INSTALL_DIR ${CMAKE_BINARY_DIR}/_install_moose_core)
 FILE(MAKE_DIRECTORY ${MOOSE_CORE_BUILD_DIR})
 set(DATA_DIR ${CMAKE_SOURCE_DIR}/data)
 
 set(OUTPUT_MOOSEBIN ${MOOSE_CORE_BUILD_DIR}/moose.bin)
 set(OUTPUT_MOOSESDIST ${MOOSE_CORE_BUILD_DIR}/moose-${MOOSE_VERSION}.tar.gz)
 
-# Options to pass down to moose-core
-option(WITH_DOC "Build documentation" OFF)
-option(DEBUG "Build with DEBUG support" OFF)
-add_custom_command(OUTPUT ${OUTPUT_MOOSEBIN} ${OUTPUT_MOOSESDIST}
-    COMMAND ${CMAKE_COMMAND} 
-        -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
-        -DDEBUG=${DEBUG}
-        -DWITH_DOC=${WITH_DOC}
-        ${MOOSE_CORE_DIR}
-    COMMAND $(MAKE)
-    WORKING_DIRECTORY ${MOOSE_CORE_BUILD_DIR}
-    VERBATIM
-    )
-
-add_custom_target(moose-all ALL
-    DEPENDS ${OUTPUT_MOOSESDIST} ${OUTPUT_MOOSEBIN}
-    )
-
-install(CODE
-    "
-    execute_process(COMMAND ctest --output-on-failure
-        WORKING_DIRECTORY ${MOOSE_CORE_BUILD_DIR})
+find_package(PythonInterp REQUIRED)
+include(ExternalProject)
+ExternalProject_Add(
+   moose-core
+   PREFIX ${CMAKE_CURRENT_BINARY_DIR}
+   SOURCE_DIR  ${CMAKE_SOURCE_DIR}/moose-core
+   BINARY_DIR ${MOOSE_CORE_BUILD_DIR}
+   CMAKE_ARGS -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER} 
+       -DCMAKE_INSTALL_PREFIX=${MOOSE_CORE_INSTALL_DIR}
+       -DPYTHON_EXECUTABLE=${PYTHON_EXECUTABLE}
+       -DDEBUG=${DEBUG}
+       -DWITH_DOC=${WITH_DOC}
+       -DWITH_BOOST=${WITH_BOOST}
+       -DWITH_MPI=${WITH_MPI}
+       -DWITH_CUDA=${WITH_CUDA}
+   TEST_BEFORE_INSTALL 1
+) 
 
-    execute_process(COMMAND ${CMAKE_COMMAND} -P cmake_install.cmake
-        WORKING_DIRECTORY ${MOOSE_CORE_BUILD_DIR})
-    "
-    )
+INCLUDE_DIRECTORIES(${CMAKE_SOURCE_DIR}}/moose-core/include)
+LINK_DIRECTORIES(${CMAKE_SOURCE_DIR}}/moose-core/lib)
 
 ## moose-gui
 ## TODO: moose-gui should be a python module.
 set(MOOSE_GUI_DIR ${CMAKE_SOURCE_DIR}/moose-gui)
 
+install(DIRECTORY ${MOOSE_CORE_INSTALL_DIR}/
+    DESTINATION ${CMAKE_INSTALL_PREFIX}
+    )
+
 install(DIRECTORY ${MOOSE_GUI_DIR}
-    DESTINATION lib/moose/gui
+    DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/moose/gui
     PATTERN ".git" EXCLUDE
     )
 

README.md

 [![Build Status - master](https://travis-ci.org/BhallaLab/moose.svg?branch=master)](https://travis-ci.org/BhallaLab/moose)
 
-This is the parent repository of [MOOSE simulator](https://moose.ncbs.res.in). It hosts components of MOOSE: core (written in C++) of MOOSE, python scripting interface, and its graphical user interface (GUI), and MOOGLI as [git-submodules](https://git-scm.com/book/en/v2/Git-Tools-Submodules). 
+This is the parent repository of [MOOSE simulator](https://moose.ncbs.res.in). It keeps the snanshots of components of MOOSE: core (written in C++) of MOOSE, python scripting interface, and its graphical user interface (GUI). This is your source 
+stable MOOSE code.
+
+# Building
+
+    mkdir _build
+    cd _build
+    cmake ..
+    make 
+    sudo make install
+
+
+# Repositories
 
 You can find detailed description of each MOOSE component in respective `README.md` in  their repositories below: