IE10 + Edge Fixes: View Camera popup correctly size & popup dialogs close properly

[shaunanoordin]

Fixes #196 Fixes issue reported by @eatyourgreens on Slack:

"Hmmm, if I open the camera popup on the map in IE10, I can’t close it again (or click on the map behind the overlay)"

Issue 1: The View Camera popup looks absolutely tiny in Edge and IE10 Analysis: In Edge/IE10, the container element (dialog-box ul) does not expand to fit its content (images) Solution: Set a specific width for the container element

Issue 2: Attempting to close a View Camera or Download CSV popup dialog causes the app to crash

Analysis:

• The DialogScreen-ViewCamera.closeMe() function (and similarly for DialogScreen-Download) isn't properly bound to the this context.
• This is because the closeMe.bind(this) call is done in the parent class (DialogScreen) constructor, but the constructor isn't being called.
• This is because Babel doesn't properly transpile the super() call into a way that works on IE10 and below: https://phabricator.babeljs.io/T3041

Solution: Make the super()call redundant by making sure the parent's (DialogScreen's) constructor is also called in the childrens' (DialogScreen-ViewCamera, DialogScreen-Download) constructors.

NOTE: Screw DialogScreen-Species, it's being made redundant in PR #209

Tested on IE10/Edge + Win7 (VirtualBox), Chrome50 + OSX

Status: Ready for review, @simoneduca and @eatyourgreens , but mind you, I'm doing some extra tests on IE10 and Edge to see what else if effing up.

[simoneduca]

LGTM.