change default style for headers to SemiBold
integrate EOT fonts into font-face styles for IE

[#42435151]
include SemiBold and Light in font-face styles

[#42435089]

Usage:

  SemiBold: font-weight: 600
  Light:    font-weight: 300
improve styling of Interactive header

[#42435089]

Search filter categories and additional links now use background
styling to make them easier to see and parse.

Titles for categories in header now have slightly darker italic
font to distinguish from category content.

Logo now is placed on layer behind the Additional Link and
Search Category rows so when browser window is narrowed
logo ends up behind clickable items.
increase height of Share pane a bit

also make <p> content SemiBold