The link to nodemcu-devkit-v1.0 was missing 'h' in 'http'. Other links were missing 'http://' or 'https://' and were pointing to non-existing components on RIOT's web site. Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Added explanation for fuse settings. Brown-out when 1.8V is set as system voltage. Power increase in deep sleep when ext. xtal as system clock.
- Cleanup brief description to be consistent with other boards - Move general documentation in doc.txt
