apply Frank Kirchner's 5.0.1B patch, 2013-07-25

From patch original header:
* applied patches from Daniel's blog comments
* updated version to 5.1.0B
* updates maxversion to 22.* (DL)

Patch was recreated and verified between v5.1.0 and v5.1.0B .xpi bundles
add syncplaces-5.1.0b-sm+fx.xpi
Merge branch 'hotfix/5.1.0B'