Update documentation

- Add "common issues" section to README
- Add more inline documentation to examples
Merge pull request #31 from box/update-docs

Update documentation
Fix ctrl+click on links in IE

In IE, ctrl+click on anchor tags cannot be caught (and default
prevented) by JavaScript. This means that ctrl+click will not be
caught and forwarded to the linkclick event handlers on the viewer.

This is a workaround where we bind a click handler on a child element
instead, and catch and stop the event.
Merge pull request #34 from box/ctrl-click-ie

Fix ctrl+click on links in IE
Fix ctrl+click on links in IE (part 2)

An addendum to my previous commit (https://github.com/box/viewer.js/commit/00094befdd5621431459ccc004e0787db8459cb7),
where ctrl+click still triggered native event behavior in IE, because
of the way jQuery event delegation works. This solves the issue by
individually installing click handlers for each link.
Merge pull request #35 from box/fix-ctrl-click-ie

Fix ctrl+click on links in IE (part 2)
Fix #37 - exceptions thrown in AJAX request handler are swallowed

The success/fail handlers for ajax.request were being called in a
try/catch statement, causing exceptions to be swallowed when thrown
from within a handler.
Merge pull request #38 from box/issue37

Fix #37 - exceptions thrown in AJAX request handler are swallowed
Merge remote-tracking branch 'origin/master' into local-files-request-fix

Conflicts:
	src/js/utilities/ajax.js