Allow entry share to be configured

In config.ini share=frde. Means facebook, readability, delicious, email
only. Respecting order.
Show/hide navigation button for desktop version
Revert "Show/hide navigation button for desktop version"

This reverts commit 3ae3114aa6ba4891af2a41f44207fd47f86ca5a3.
Merge pull request #390 from kucoe/master

Allow entry share to be configured