(fix) centers splash form, adjusts font size, changes submit to search, adds spacing on login, minor styling adjustments

1. centers form and submit [SPLASH]
2. changes size of title and tag line [SPLASH]
6. Changes “SUBMIT” button to “SEARCH” [SPLASH]
7. Changes spacing on login/signup templates for login button [LOGIN/SIGNUP POPUP]
8. Changes “OKAY” to either “login” or “signup” for login/signup templates [LOGIN/SIGNUP POPUP]
9. Adds Facebook logo for “SIGN UP WITH FACEBOOK” button [LOGIN/SIGNUP POPUP]
10. Adds split dividers for “or” so it looks like “ — or —“ [LOGIN/SIGNUP POPUP]
12. Changes font color for input form [PRIVATE PROFILE]
13. Centers submit button [PRIVATE PROFILE]
14. Adds max width and center sitters on page [SEARCH]
16. Makes input form clearer and easier to see [SEARCH]
17. Changes sitter card colors to stand out from page [SEARCH]