append words to default wordlist

[sbakhit]

I understand you can have your own custom wordlist and even make it default. it would be great if one can also append to the current default. The default one works great for me except for a few words that are not there.

[shullaw]

wordninja.DEFAULT_LANGUAGE_MODEL = wordninja.LanguageModel('my_lang.txt.gz')

I think you can just go find this file, and add to it. The only thing you'd have to figure out is what is the probability of the word you are adding? I believe the words are in a list, line by line, of descending probability.

[sbakhit]

I added this PR to make it easier to achieve this. feel free to discard it you don't agree.

[keredson]

they are in descending probability. i didn't add this as a feature because i didn't have any good ideas as to how to express that probability when adding. but likely adding it to the end of the files is a good default strategy. (better than nothing certainly!)

[kapilmeena]

@keredson "I have some names which i want to change dynamically .." I think this is the use case where we need to add words in starting of file so they can have highest priority then english launguage.