Beem

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* get_node_answer_time added to NodeList
* New node added
* new stored parameter: default_canonical_url
* beempy notifications sorting is reversed, a new parameter can be used to change the sorting
* New beempy createpost command, it can be used to create an empty markdown file with YAML header for a new post
* beempy post has now a canonical_url parameter, when not set, default_canonical_url is set
* New beempy draw command, can be used to generate pseudo random number from block identifiers using hashsums
* remove enum34 dependency

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* Improve chain detection (Steem chain detection fixed and preparing for Hive HF24)
* Add authored_by and description fields in YAMLM header
* Improve doc
* beempy post image upload includes the markdown file path now

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* Missing dongle.close() added (thanks to netuoso)

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* Fix update_account_jsonmetadata and add posting_json_metadata property to Account
* Add Ledger Nano S support
* beempy -u activates ledger signing
* beempy -u listkeys shows pubkey from ledger
* beempy -u listaccounts searches for accounts that have pubkey derived from attached ledger
* beempy -u keygen creates pubkey lists that can be used for newaccount and changekeys
* new option use_ledger and path for Hive
* Allow role selection in keygen

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* beempy --key key_list.json command can be used to set keys in beempy without using the wallet.

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* Add missing diff_match_patch to requirements
* beempy download without providing a permlink will download all posts
* Improve Yaml parsing