Many .vimrc changes.

- Add solarized
- Add fugitive
- Append to fillchars instead of replacing
- Increase GUI font size from 11 to 12
- Increase all tab sizes from 3 to 4
- Add cscope options and mappings
- Add nicer looking fold text function
- Add mappings and commands for dates/times
- Use more appropriate terminology in comments (mappings vs. keybinds)