Merge branch 'hotfix-1.0.1' into stable
release 1.1

- support for API 7 (websockets)
- use submodules for example applications
- new binary registration response format (JSON style)
- some unit tests (draft)
- doxygen documentation
- basic tools refactoring:
  - http: support for websocket connections, base64
  - log: support for log file size limit
  - json: ordered member list of JSON object, strings without quotes
and much more...
merge stable back to support `git describe`
example of log configuration in JSON format

log::Target::File auxiliary methods (getters and setters)
minor documentation changes
bump doxygen doxumentation version

websocket as basic tools` subpage
HTTP module bug fix: 'query' part was missed in the http request first line

http: request first line should contain 'path' and 'query' parts
log: avoid streamsize to size_t warning
support 'timestamp' parameter for a "command/poll" request

update cloud6::Command to support 'timestamp' property (UTC date and time as simple string)
update simple_dev/simple_gw/zigbee_gw examples (REST) to support the last received command timestamp

NOTE: this 'timestamp' is valid during application lifetime only, to be able to process "offline" commands (which are received by server while application is not running) this 'timestamp' parameter should be saved between application runs.
support for device's custom data
support for /info request which returns server information

"serverTimestamp" is used to start polling commands from the gateway starting time
Merge branch 'master' into doxygen
update doxygen documentation (HTML)
merge the latest documentation