resizes welcome image to fit 320px width screen
changes portfolio content to all be full width of portfolio section
modifies popups for portfolio projects slightly (changes link styling)
Modifies footer link size and removes 'connect via' text at <= 450px
Modifies footer media query from min 450 px to min 540 px
Resizes top content div to fixed height at smaller device size
Sets fixed width for logo at smaller device size
Merge pull request #11 from mh120888/mobile-second-round

Mobile second round