Add command so preserve can make some maps easier

I couldn't figure out a way to make preserve work when trying to use the
built in normal command and at the same time  correctly handle keys
represented by with brackets enclosing them like <CR> and <BS>. So I
added a command to simplify the process.

Example:
nnoremap <silent> *  :PreserveSave<CR>:normal! *N<CR>:set hlsearch<CR>:PreserveRestore<CR>

And btw I was the one on reddit to suggest winsaveview() & winrestview()
Remove the mappings from the plugin

The README doesn't mention providing any mappings, and also suggests
adding these same mappings, so I don't think they should be included in
the plugin