Add line numbers to ruler and sidebar.

Vim now has sidebar numbers that are realtive to the cursor. You
can also see in the ruler the line number. The first number is the
line your are on and the second number after the comma is the
number where the cursor is. I am adding all three settings to one
commit as they are related.
Change the leader key to a comma

The leader key is a key that is pressed before some of the custom
commands that can be created in VIM. Later there will be commands
written like `map <leader>abc` which translats to `,abc`.
Set the word wrap character limit to 78

I did this because I want to try and keep my lines of text and code
short. I belive the regular limit is 80 characters but I've seen this
change in other .vim files and I figured it would be good to add.
Underline the cursors current line

I did this because in other text editors I liked having the current
line highlighted slightly for faster identifying. I don't know if
a feature like that exists without a GUI so I will try this for now.
Add Base16 ocean color scheme

This was very difficult to get set up and even now that it's done
I don't think it's completely there. This set up required me to make
the switch to iTerm instead Terminal. There are conflicts with 256 and
base16 themes with Terminal and it was simpler to switch applications.

I created a colors dir and included the `.vim` files needed to support
the ocean theme(as well as some others). I also included the
base16-shell scripts in my `~/.config` dir where I could test that
my 256 colors were indeed working. In iTerm I double clicked on
downloaded `.itermcolor` files to include the needed ocean color
themes for iTerm and created a new template.

This has been the most frustrating thing thus far and I'm sure this
won't be the last time that color themes will create issues for me.