Kernel: Improve on screen printing

[StraykerPL]

Hi there! :D

Strayex Kernel has got three functions:

kprintch kvprintf kprintf

They are responsible for printing on screen characters. This functions do not meet the requirements of C language standard, some of them need improvement and some thing have to be finished.

Working with these functions can be good programming exercise and it will relieve me form additional work.

Things to do here are:

• find unfinished functions in these list,
• look into code and find lines, that can be improved,

These functions are very inportand to kernel work! Before submitting pull request, compile kernel in debug mode (in this version default one) and check that Multiboot data is displayed properly.

Remember, every change done in system must be updated in documentation!

Good luck and have fun! 👍