* doc: cleanup and key-value for optional parameters
* rebalance: cleanup and refinements
* sendinvoiceless: cleanup and refinements
* summary: reflects upcoming changes of pylightning to_approx_str
* rebalance: check peer connection on local channels
When the summary plugin starts, it runs a thread to discover the current
`fiat_per_btc` price. When this was not finished yet, the `if` statement
in line 112 fails, because this in not JavaScript and the property has
to be checked with `hasattr(obj, key)` method in order to not throw an
exception.
Improves some minor output issues:
- Adds short channel id, so it can be copy and pasted for rebalancing
- renames `channels_key` to `channels_flags`
- changes flags round rackets (PO) to squace brackets [PO]
- Always outputs flags even if not set [__] so things are always aligned
- Removes the colon ':' and always prints a space
this also helps when copy and pasting in a terminal
