Merge from old nuttx branch:

commit 4571d52e801252b8ec00374d4c993d7c022f339a
Author: Librae <librae8226@gmail.com>

	config: leach: enable i2c bus and app tools

commit a00eaa0577580bc936b1480bec8616997e06de58
Author: Librae <librae8226@gmail.com>

	config: leach: update defconfig

commit ddc51ea264b053bea39715fd4455e681e9d3fb08
Author: Librae <librae8226@gmail.com>

	config: leach: update defconfig

commit 0020e558a2c8ab469965540f8010af203e5f0ab2
Author: Librae <librae8226@gmail.com>

	arm: stm32: add stm32f103cb support

commit b5a3607e1bde1393dbab7f6e893eca5103a92726
Author: Librae <librae8226@gmail.com>

	config: leach: update and cleanup source

commit 94de872e1027ac1f77daf93b4182a96d9ad4dd7f
Author: Librae <librae8226@gmail.com>

	cleanup: arm, configs, debug

commit b2789ceffd8ef0351c5bb57ace157e16faca7adf
Author: Librae <librae8226@gmail.com>

	config: add leach-stm32, derive from hymini

commit 2bcd906339ca00f21fccb7729f406aabdf813a7a
Author: Librae <librae8226@gmail.com>

	drivers: serial: revert a hack

commit 65b90e3e292c80c7ff59118230901411769ba1a5
Author: Librae <librae8226@gmail.com>

	arm: stm32: update config, enable
	cdcacm console

commit c06911bf5a513fa3a6799d18dbeb6948f605b6d1
Author: Librae <librae8226@gmail.com>

    arm: stm32: update script and config

commit f25ea563dc332567a8bd977e1f5069142d6024c1
Author: Librae <librae8226@gmail.com>

    configs: fix the incorrect chip name config item

commit e042bc4f48dfe075f8558a240f2c2520ecffe177
Author: Librae <librae8226@gmail.com>

    arm: stm32: hack, force send '\r'.

commit 06b67b81a5b24b8fa10d4a395586017bca9d4d9a
Author: Librae <librae8226@gmail.com>

    arm: stm32: update appconfig

commit ba40e7620b74437cbee3d5eb6c27092ccfee7df6
Author: Librae <librae8226@gmail.com>

    arm: stm32: porting on stm32f103cbt6
apps: usbterm: do some customization test
configs: leach: update defconfig