Minor improvements to restructuring outcomes.
Updates to word substitutions.
Updates to logging.
Fixed failing translation test.
Streamlined tokenizer.
Updated comments.
Retain a word's original letters where phonemes haven't been substituted.

Rather than a completely phonetic transformation of, for example, come -> koom
like -> liyk, the relevant original letters of come and the original spelling
of like are retained i.e. come -> coome, like -> like. This provides a more
readable result.

The original method of completely phonetic spelling is still available
by setting phonetic=True in translator.alter_phonemes().
Improved handling of repeated letters e.g. 'account' vs 'accept'.

Also added 'ss' as a possible spelling for phoneme 'SH' e.g. in
'session.
Updated consonant markers.
Refactoring.