Finish development of new text language detection engine

[rotemdan]

The current two engines (tinyld and fasttext) aren't always accurate and sometime produce odd or nonsensical classifications, like classifying English text as Klingon.

I've developed a custom engine, based on N-grams and naïve Bayes inference, with high accuracy, supporting more than 100 languages. However, the work isn't fully ready yet.

Things left to be done:

• Compile and optimize model data as a single binary file
• Only include shorter N-grams for some easy-to-classify languages like Chinese and Japanese
• Decide if to include less common languages, or how to produce smaller and larger variants of the model with varying sets of supported languages