TVB-72
Review code and clenup.

git-svn-id: https://repo.thevirtualbrain.org/svn/tvb/trunk/framework_tvb@5003 1c0e02f0-7929-43c0-8fb3-3293bf43b0d1
TVB-966
When an algorithms gets deleted from DB, do not remove WorkflowSteps in cascade, to allow reconstruction in case of errors.

git-svn-id: https://repo.thevirtualbrain.org/svn/tvb/trunk/framework_tvb@5004 1c0e02f0-7929-43c0-8fb3-3293bf43b0d1
TVB-72
Fix wrong size on legend canvas for weights table.

git-svn-id: https://repo.thevirtualbrain.org/svn/tvb/trunk/framework_tvb@5005 1c0e02f0-7929-43c0-8fb3-3293bf43b0d1
TVB-72
Add export as Image functionality for PSE-Isocline viewer.

git-svn-id: https://repo.thevirtualbrain.org/svn/tvb/trunk/framework_tvb@5006 1c0e02f0-7929-43c0-8fb3-3293bf43b0d1
TVB-72
Add export as Image functionality for Histogram Viewer.

git-svn-id: https://repo.thevirtualbrain.org/svn/tvb/trunk/framework_tvb@5007 1c0e02f0-7929-43c0-8fb3-3293bf43b0d1