Merge pull request #10 from slima4/master

implemented getLastImages
добавлен zcore-stub, теперь gstreamer не нужен для большей части разработки.
Merge pull request #11 from slima4/master

getLastImage
Merge pull request #12 from slima4/master

ticket 4: added image dialog
PreviewWidget: Fit and Stratch modes added
Merge pull request #15 from mbg033/master

PreviewWidget
stub implementations
clean
merge