Create 08_SentenceExtractor.cs

08. Write a program that extracts from a given text all sentences containing given word.
Example: The word is "in". The text is:
We are living in a yellow submarine. We don't have anything else. Inside the submarine is very tight. So we are drinking all the day. We will move out of it in 5 days.
 
The expected result is:
We are living in a yellow submarine. We will move out of it in 5 days.
 
Consider that the sentences are separated by "." and the words – by non-letter symbols.