Added CMake build system

.gitignore

.gitlab-ci.yml

CMakeLists.txt

mbs

miosix/_examples/sad_trombone/player.cpp

miosix/_examples/thread_native/native_thread_example.cpp

miosix/_examples/thread_pthread/pthread_example.cpp

miosix/_tools/fs_misc_testcode/dirlist.cpp

miosix/_tools/ram_test/main.cpp

miosix/cmake/boards.cmake

miosix/cmake/mbs.cmake

miosix/cmake/miosix.cmake

miosix/cmake/toolchain.cmake

...rch/arm7_lpc2000/lpc2138_miosix_board/board_options.cmake

..._stm32f0/stm32f072rb_stm32f0discovery/board_options.cmake

...exM3_efm32gg/efm32gg332f1024_wandstem/board_options.cmake

...rtexM3_stm32f1/stm32f100c8_microboard/board_options.cmake

...exM3_stm32f1/stm32f100c8_vaisala_rs41/board_options.cmake

...rtexM3_stm32f1/stm32f100cb_tempsensor/board_options.cmake

.../cortexM3_stm32f1/stm32f100cx_generic/board_options.cmake