V0.3: [added] Lemmatizer to lemmatize sentences into a List of string tokens
V0.3: [updated] Minor refactoring
V0.3: [added] GrammaticalParser is to parse a sentence in order to understand the grammar within the sentence structure
V0.3.1: [updated] Minor Refactoring
V0.3.2: [updated] changed access modifiers to 'private'
V0.3.2: [added] NLPEngine mutes and restores NLP error messages
V0.3.2: [updated] added comments to the methods
V0.3.3: [added] Sentiment Analysis. Allow developers to analyze users sentiments from their input
V0.3.4: [added] TimeValidator validates the time to be in 24-hour pattern
V0.3.4: [added] SentenceStructure breaks the sentence into individual tokens in order to identify the dependencies based on node relations & extracts the date & time values from the sentence