WIP: Moved sources int src/, separated most of the source code from Perl.

The XS was left only for the unit / integration tests, and it links
libslic3r only. No wxWidgets are allowed to be used from Perl starting
from now.

src/libnest2d/tests/CMakeLists.txt

@@ -0,0 +1,51 @@
+
+# Try to find existing GTest installation
+find_package(GTest 1.7)
+
+if(NOT GTEST_FOUND)
+    message(STATUS "GTest not found so downloading...")
+    # Go and download google test framework, integrate it with the build
+    set(GTEST_LIBS_TO_LINK gtest gtest_main)
+
+    if (CMAKE_VERSION VERSION_LESS 3.2)
+        set(UPDATE_DISCONNECTED_IF_AVAILABLE "")
+    else()
+        set(UPDATE_DISCONNECTED_IF_AVAILABLE "UPDATE_DISCONNECTED 1")
+    endif()
+
+    include(DownloadProject)
+    download_project(PROJ                googletest
+                     GIT_REPOSITORY      https://github.com/google/googletest.git
+                     GIT_TAG             release-1.7.0
+                     ${UPDATE_DISCONNECTED_IF_AVAILABLE}
+    )
+
+    # Prevent GoogleTest from overriding our compiler/linker options
+    # when building with Visual Studio
+    set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+
+    add_subdirectory(${googletest_SOURCE_DIR}
+                     ${googletest_BINARY_DIR}
+                     )
+
+    set(GTEST_INCLUDE_DIRS ${googletest_SOURCE_DIR}/include)
+
+else()
+    find_package(Threads REQUIRED)
+    set(GTEST_LIBS_TO_LINK  ${GTEST_BOTH_LIBRARIES}  Threads::Threads)
+endif()
+
+add_executable(bp2d_tests   test.cpp
+                            ../tools/svgtools.hpp
+#                            ../tools/libnfpglue.hpp
+#                            ../tools/libnfpglue.cpp
+                            printer_parts.h
+                            printer_parts.cpp
+                            ${LIBNEST2D_SRCFILES}
+                            )
+target_link_libraries(bp2d_tests ${LIBNEST2D_LIBRARIES} ${GTEST_LIBS_TO_LINK} )
+
+target_include_directories(bp2d_tests PRIVATE BEFORE ${LIBNEST2D_HEADERS}
+                                                     ${GTEST_INCLUDE_DIRS})
+
+add_test(libnest2d_tests bp2d_tests)