Removed 'integrate' from to-do
Implemented SvgCanvas.clear()
Refactored initializeDrawingArea() to take object with elements
Implemented test for 'clear screen' button
Updated Safari 6.1.2 --> 6.1.3
Implemented event handler for 'clear screen' button
Added 'clear screen' button to HTML and styled it minimally
Implemented HtmlElement.fromId()
Refactored index.html to use HtmlElement.fromId()
HtmlElement.fromId() fails fast when ID not found
Added fail_fast.js
Modified client.js and html_element.js to use new fail_fast.js module
Hacked in solution to Raphael bug that causes sub-pixel gap
Updated to-do
Upgraded JQuery 1.8.2 --> minified 1.8.3
Upgraded Raphael 2.1.0 --> 2.1.2
Upgraded Modernizr 2.6.2 --> 2.7.2
Styled 'clear screen' button
Revised site copy; converted 'clear screen' button to <button> for iOS display
Merge branch 'master' into integration

* master:
  Revised site copy; converted 'clear screen' button to <button> for iOS display
  Styled 'clear screen' button
  Upgraded Modernizr 2.6.2 --> 2.7.2
  Upgraded Raphael 2.1.0 --> 2.1.2
  Upgraded JQuery 1.8.2 --> minified 1.8.3
  Updated to-do
  Hacked in solution to Raphael bug that causes sub-pixel gap
  Modified client.js and html_element.js to use new fail_fast.js module
  Added fail_fast.js
  HtmlElement.fromId() fails fast when ID not found
  Refactored index.html to use HtmlElement.fromId()
  Implemented HtmlElement.fromId()
  Added 'clear screen' button to HTML and styled it minimally
  Implemented event handler for 'clear screen' button
  Updated Safari 6.1.2 --> 6.1.3
  Implemented test for 'clear screen' button
  Refactored initializeDrawingArea() to take object with elements
  Implemented SvgCanvas.clear()
  Removed 'integrate' from to-do