osutil: doc on Username

Change-Id: Ic6deb921e9fb7cdce34e4e50143b321b6aedd697
website: fix redirection of some /gw/ links

Change-Id: I524ee2dd48fa16c4b3954fdf58878b7256702347
Merge branch 'master' of https://camlistore.googlesource.com/camlistore