add new fields to sourcestampsets table

add new fields to save information about artifact in sourcestampsets
table
implement query to get artifactgui

getartifact gui given a list of sourcestamps on current build
update sourcestamp table with new revisions

after git/hg commands execute update sourcestamps table with latest
revistion, switched to use dictionary parameter
update sourcestampsets table with multiple repo guid

- update sourcestampsets table with multiple repo guid
- check parameters arent null
add CheckArtifactCommand

command use to check if the artifact has been already generated by a
different build having the same sourcestamps (codebase x revision)
update sourcestampset CheckArtifactCommand

update sourcestampset if artifact has been already generated
add ArtifactUploadedCommand

when the build finish uploading the artifact, update sourcestampset and
provide a link
add suppport for clean build (this will generate new artifact)

when making a clean build a new artifact will be generated, following
builds will use this.
define artifactguid in build property, check sourcestampset.artifact_guid isnt null
add index to model