Fix wrong model recognition

Parser was recognizing words with `model` keyword combination, for example `` `model` `` or `Cmodel`, as model, this is a suggestion to fix the issue. this pull request would close issue #92 and #152.
> +model (no space between model and starting of the string) 

This is incorrect, if there is a `+` followed immediately by a non-blank character – it is not a markdown list but a paragraph and should not be recognized what so ever