Merge pull request #262 from pillo79/pr-fixes-post-0.52

trivial: minor fixes for 0.52

extra/gen_package_index_json.sh: fix JSON format

Merge pull request #168 from iabdalkader/bt_fixes

loader: Export BT firmware symbols.

README: clarify Windows is unsupported, but WSL is a workaround

platform: fix paths with spaces

Wrap problematic arguments in quotes to avoid issues with paths that
contain spaces (especially on Windows).

platform: fix paths with spaces

Wrap problematic arguments in quotes to avoid issues with paths that
contain spaces (especially on Windows).

loader: move dhcp server in own ifdef

mass rebuild

zephyrSerial: Fix misdetection arduino_serial1

DT_NODE_EXISTS value is true even if the status is disabled,
so it caused misdetection.
Use DT_NODE_HAS_STATUS to detect the status of
the arduino_serial1 node is ok.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>

documentation: Add document about `builtin-led-gpios`

Add a description for `builtin-led-gpios`

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@fujitsu.com>