- Impacts also the history loading

- Remove call of refreshing from the UI
- Handle refresh tasks from the core
- When a refresh is running, wait for it to finish
- Change the latest block to parse during the refresh coroutine
if the latest block changed

- New txhistory uses db indexation of ucoin nodes which is buggy atm
- Implemented the old txhistory algorithm to fix this problem temporarily

Replaced every bma_access.get with future_request
All network requests are now done in coroutines except simple_requests

- Sending money
- Sending certification
- Sending membership

To be tested...