Fix account creation test
issue_asset_type as class
add test for write_cheque
Add Cheque class to make test-level abstraction

   Still get error that time64_t doesn't accept python's int

Add flake8 config
use utc time
Fix some references to undefined fields
fix issue_asset_type
Merge pull request #3 from mhamrle/test_write_cheque

add test for write_cheque
check accounts balance before and after transfer
Merge pull request #6 from mhamrle/test_write_cheque

check accounts balance before and after transfer
Fix misspelled requirement
Don't try to remove ~/.ot if it's not there