Remove MONGOOSE_NO_DAV on DAV_AUTH_FILE options

Building with -DMONGOOSE_NO_DAV will fail.
Tyop fix.
Merge pull request #351 from da4089/master

Tyop fix.
Merge pull request #350 from solomonhuang/nodav

Remove MONGOOSE_NO_DAV on DAV_AUTH_FILE options
updated faw and tutorials