Switch back the checksum delimiter from "!" to ":" as '!' should be escaped on non-fish shell (bash, zsh). Possible since the tx pubkeys delimiter is no longer "!"
Hi,
For issue #111 I don't get how the checksum syntax works.
There is only [one call to the check_public_key() function](https://git.duniter.org/clients/python/silkaj/blob/dev/silkaj/tx.py#L121), and it does not get the pubkey without checksum.
I tried using this feature, it does not work :
```
silkaj -p ts.gt.librelois.fr tx --output=J4c8CARmP9vAFNGtHRuzx14zvxojyRWHW2darguVqjtX!KAv --amount 1 --comment "BABA YAGA"
bash: !KAv: event not found
```
How do I get it to work ? Or should I make a MR without bothering ?a
issue