split vimrc in organized sections and add few stuffs

    add backspace config
    add scrolloff config
    add history remember to 100
    add extention %% to current dir
    add <leader>a to toggle to alternative buffer
    add <leader>p to indent after pasting
    add markdown filetype setting for extensions like md, mdown, ...
    remove line moving mapping cuz it don't work & we have unimpaired
update oh-my-zsh