Scrolling up animation on scroll up button in footer (Issue #30) solved

[Swatilekha-Roy]

• Added scroll up animation to the scroll up button of footer
• Adjusted the js code so as to make the button appear only when we are at the bottom of page
• Also further added slide in animation to footer, so it pops up only when at the bottom of page and disappears when we scroll up from screen.
• Have also resolved conflicts and fork is upstream. Hope that solves the issue! Please reach out if there is anything that you think needs to be changed, @chehak123. Thanks!