Add support for files that uses CRLF

[MXD-K1]

This PR:

• Adds support for files that uses CRLF line endings.
• Clears the visible text after exiting the program.
• Changes buffer size in char singleline_comment_start[2]; from 2 to 3 to account for null terminator.
• Removes unused include header.
• Fixes some typos.