Edit improvements to English text

For Issue #420. These edits fix grammatical mistakes, correct capitalization of many words, fix overuse of certain types of punctuation, and generally make the text more consistent and easier to read. Especially for the dialogs that occur between characters in the game. Hope you like these changes. It took me several hours to go through every line of text in the game.
Ah, yes that is supposed to be an 'at'.