changes in README.md to ease my frustration

[Tadek1]

I am too green to make changes in the install process of dotfiles. My original frustration was that after installing dotfiles, I had error displayed while starting vim:
Error detected while processing /home/tad/.vimrc: line 65: E185: Cannot find color scheme 'solarized' Press ENTER or type command to continue
and colours where not displayed 'solarized'. After long investigation (learning vim and git) I figured out the culprit: plugins must be installed first.

There was another problem with another plugin which required MAC (zerowidth/vim-copy-as-rtf?), but it is beyond the scope of this pull request.

Long story short: it takes longer then a week to learn vim.

[mscoutermarsh]

Hi @Tadek1!

Thanks! Appreciate it! Going to take a look at this soon + will add in some other changes to make it easier to understand.