Resolve "Modbus allow word order swap"

Summary

Adding the option to use little endian word order. This can be set via a new modbus attribute mb_wordorder.

Only applicable for 32/64bit int/float values.

Please list breaking changes, new features or bugfixes

• Breaking changes:

• New features:

  • word order handling for modbus nodes

• Bugfixes:

  • fixes emonio reading

Closes #253 (closed)