Move svg element into dep-tree template

Use a div to embed the tree. Now firefox can display the tree,
although the svg size isn't right yet.
Try e2e on firefox
Fix head change test and deactivate first tree test
Make svg full width and height for firefox
Add more sauce lab tests
Add IE and Safari
Change server port to 8081 for IE and Safari on saucelabs
Fix of internet explorer test specification
Update readme with new dev port
Disable IE and Safari for now
Merge pull request #141 from latin-language-toolkit/fixing_the_tree

Fixing tree for firefox and add firefox to supported/tested browsers