Fix an error with saving the hash value. Also added storing the hash and last modified timestamp on install.
Fix an error with saving the hash value. Also added storing the hash and last modified timestamp on install.

Ventero/greasemonkey,HasClass0/greasemonkey,Martii/greasemonkey,the8472/greasemonkey,the8472/greasemonkey,Ventero/greasemonkey,Martii/greasemonkey,HasClass0/greasemonkey