Split totalised transactions

v2.8

also split for type 2 + revert add structured message to message

Expose client reference

Add property to expose client reference

Support for php8.1

Remove warnings when using php8.1

Fix collective transactions

Don't skip collective transactions when no detail transactions present.
Throw error when no transaction part 1 present.

Collective transactions

Adding support for collective transactions

Expose additional fields

Update .travis.yml

remove php 7.2 and lower for phpunit

Expose statement and transaction number

Added new getters to expose the statement and transaction sequence numbers

fix encoding

Fix encoding when reading from file

Fix inconsistency for AccountOtherParty class

v2.1

fix inconsistency with other Account class

Parser reworked with stricter input checks

PHP 7.0 or higher only
Use getters and setters with defined type
More checks on invalid data when parsing files