Replaced navbar logo with new file

Replaced 105px logo image in theme/images/ with new 124px logo.
Updated navbar address size

Changed from font-size 9px / line-height 11px to font-size 11px /
line-height 13px
Updated "p a"  line-height from 21px to 24px
Updated .page-unit .section margins

Changed left-magin from 280px to 250px and right-margin from 100px to
10px
Updated .page-unit .inner-container

padding-bottom from 120px to 80px and margin-bottom from 80px to 50px
H1 padding and H2 line-height

Updated H1 padding and added H2 line-height:20px;
Updated "ul li" font-size and line-height
Added "Our Approach" section and functionality

Added approach images to assets/images/approach
Created approach content section within index.html based on portfolio
design.
Added show_approach() to js to display approach section (based on
portfolio functionality).
Revised js to change hide_portfolio() to
hide_special_content_elements() to test for and incorporate approach
section in addition to portfolio section (and allow for future
sections).
Updates to responsive formating

Mobile:
# resized logo
# adjusted nav menu font-size, line-height, padding
# adjusted p font-size, line-height, changed from pt to px
# adjusted blockquote
# responsive layout of brand assembly images

Tablet:
# adjusted some some font-sizes, line-heights, margins, etc.
Moved contents into index.html