v1.3.0 URLs and variable screen size

Features:

• Added Urls as a slice of strings in all relevant functions
• All visual items (input fields and text columns) are calculated to resize to look good in different sized terminals
• / is optional to start off commands, open is the same as /open
• /open's sensitive information that is colored the same as the background is now highlighted the same color as the text -- assurance against a possible future background change
• Changed text prompting in delete entry pop up

Bug fixing / refactoring:

• All instances of fmt.Sprint(str, str) for string concatenation have been swapped to str + str or string builder using + b.WriteString(str + str), as I found those to be faster than fmt.Sprint in benchmark tests
• Spelling mistakes fixed
• Alphabet iterator is now an int, not a struct
• Each time /help and /open are called, the page will start scrolled up at the top
• /flist str now shows the entries not in circulation (like /find)
• Moved writeToFile, readFromFile, and the entry struct to encrypt.go so that it can be imported into changeKey.go and createEncre.go
• README updated
• All files are gofmt formatted
• Input fields in both the password screen and home screen will only be done once user clicks enter/return or tab; no longer arrows or back tab

Full Changelog: v1.2.1...v1.3.0