Update changelog
File move

Move 'test_ioprocessor' to 'test_iomanager'.
Organize docs

Move 'README.txt' to 'REATME.md'.

Update 'project_history.txt'.
Method tests

Add test for separate 'coerce' and 'verify' methods of 'IOManager class.
IOManager methods

Implement separate 'coerce' and 'verify' methods of 'IOManager' for
'input' and 'output' routines.

All tests pass.
README

Add information and examples to README.

'VerificationFailureError' assigns error message to 'error_msg'
attribute.
Merge branch 'dev/documentation' into develop