Add support for relative urls of dependencies. For scripts already installed that have relative urls, this commit keeps those dependencies from being deleted. For scripts installed in the future, the download url is saved in the config.xml so that relative dependencies can be redownloaded.
Add support for relative urls of dependencies. For scripts already installed that have relative urls, this commit keeps those dependencies from being deleted. For scripts installed in the future, the download url is saved in the config.xml so that relative dependencies can be redownloaded.

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