Training should use the chat bot's preprocessors

[gunthercox]

Currently, when a chat bot is trained, the dialog is saved directly to the database. This needs to be changed so that the training data can be cleaned and tagged by the chat bot's preprocessors.

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Related to #954 (comment)

[isaam14]

@gunthercox What can I do if I don't want the training to be done with preprocessors? (because the preprocessors I use convert uppercase and unicode to lowercase and ascci respectively, but I want the responses to have uppercase and unicode in some cases)
Is there a way to set the preprocessors after the training?