added back *.opensdf files to .gitignore.
added back *.opensdf files to .gitignore.

luisbarrancos/appleseed,docwhite/appleseed,aiivashchenko/appleseed,pjessesco/appleseed,Vertexwahn/appleseed,appleseedhq/appleseed,Biart95/appleseed,aytekaman/appleseed,Aakash1312/appleseed,aiivashchenko/appleseed,Biart95/appleseed,pjessesco/appleseed,Biart95/appleseed,Vertexwahn/appleseed,luisbarrancos/appleseed,docwhite/appleseed,est77/appleseed,dictoon/appleseed,Vertexwahn/appleseed,pjessesco/appleseed,est77/appleseed,glebmish/appleseed,appleseedhq/appleseed,glebmish/appleseed,glebmish/appleseed,gospodnetic/appleseed,Vertexwahn/appleseed,dictoon/appleseed,gospodnetic/appleseed,Vertexwahn/appleseed,appleseedhq/appleseed,aiivashchenko/appleseed,glebmish/appleseed,appleseedhq/appleseed,pjessesco/appleseed,Aakash1312/appleseed,luisbarrancos/appleseed,aiivashchenko/appleseed,dictoon/appleseed,luisbarrancos/appleseed,Aakash1312/appleseed,glebmish/appleseed,Aakash1312/appleseed,est77/appleseed,est77/appleseed,est77/appleseed,docwhite/appleseed,gospodnetic/appleseed,gospodnetic/appleseed,dictoon/appleseed,aytekaman/appleseed,aytekaman/appleseed,gospodnetic/appleseed,Aakash1312/appleseed,docwhite/appleseed,luisbarrancos/appleseed,pjessesco/appleseed,dictoon/appleseed,Biart95/appleseed,appleseedhq/appleseed,aytekaman/appleseed,docwhite/appleseed,aytekaman/appleseed,Biart95/appleseed,aiivashchenko/appleseed