Fixed logical error

The if/else statement determining whether to encrypt or decrypt the key
was only applying the rolling back to Decrypted messages.
Added “{}”s around the if/else statement, preventing the logical error.
Logical Error Fix & Punctuation addition

Found out logical error with Decryption, would always capitalize
lowercase letters
Fixed logical error
Added “or” statements for punctuation in addition to spaces
Punctuation addition

Added apostrophe to punctuation list