Fix text encoding dialog

Same issue and fix as the Seahorse bug below:

https://bugzilla.gnome.org/show_bug.cgi?id=703825
Updated Hebrew translation
Remove all WebKit1 code

We are using WebKit2 unconditionally already.
Center and expand tabs

https://bugzilla.gnome.org/show_bug.cgi?id=709444
web-extension: do not pass data uris through the uri tester

As this is always going to fail. Also it can be pretty slow
for large data.
Create a find toolbar to each tab

https://bugzilla.gnome.org/show_bug.cgi?id=710542
ephy-find-toolbar: Close the search bar when loading new page in the current tab

https://bugzilla.gnome.org/show_bug.cgi?id=710542
ephy-find-toolbar: Remove unused variable
prefs: use GtkDialog instead of EphyDialog

https://bugzilla.gnome.org/show_bug.cgi?id=720098
prefs: make the dialog modal

https://bugzilla.gnome.org/show_bug.cgi?id=720098