Merge pull request logdna#18 from SpainTrain/support-tags

feat(tags): Allow tags to be configured

bump to 1.2.6

ensure we properly call gethostname from socket

Readme updates, plus adds the ability to pass ip/mac addresses

ensure sanitized keys are added to the __errors object as a string

sanitize meta values that are not JSON serializable, include a refere…

…nce to the respective key in the meta.__errors.sanitizedKeys array

ensure that LogDNA module recovers after internet reconnects