Improve facebook sharing dialog

[virtser]

1. ~Make its size smaller.~
2. ~Keep only 3 top groups to share.~
3. Add Facebook logo to groups and update the colors.
4. Remove the 'x' close buttons (so that users will have to choose if they want to see it again)
5. ~Open after 3 seconds delay.~
6. ~Add top groups for Haifa, Jerusalem and Beer Sheva. Please find the groups details here:~ https://docs.google.com/a/dorbel.com/spreadsheets/d/1LcC9R0KtY-QvtfzKV7bjEAUV19ri0ay8FkCEback4D4/edit?usp=sheets_home&ths=true

[zivoko]

@virtser ready

[amoslande]

@virtser I removed the close button... but ESC can still be used did you take that under consideration? (also when clicking outside on the backdrop...)

[virtser]

Yes, that's OK