:tada: Added .gitattributes & .gitignore files
Revert ":tada: Added .gitattributes & .gitignore files"

This reverts commit ba6f5d9d53ec4b52d9ec9478384226d1b3c76fa6.
Add DDA and Bresenham algorithm.

*.hpprgm only can be read in HP Prime or HP Prime emulator, and each
hpprgm file acconpanied with an ASCII file show their source code.