Merge pull request #12 from sheetbrick/dev

dev to master merged
Update README.md
Fix page visibilit issue on Mozilla (Issue #14)
Merge pull request #15 from deathangelisme/master

Fix page visibilit issue on Mozilla (Issue #14) merged to master
Fix freezing when logging in and out using multiple users (Issue #13)
Merge pull request #16 from deathangelisme/dev

Fix freezing when logging in and out using multiple users (Issue #13) merged to master
Merge pull request #17 from sheetbrick/master

Master to dev merged