Fixed file objects with hyphen issue (ucfopen#647 ) and added test cases #650

nayanpaa wants to merge 8 commits intoucfopen:developucfopen/canvasapi:developfrom

nayanpaa:issue/647-File-objects-get-attribute-content-type-which-must-be-accessed-through-getattrnayanpaa/canvasapi:issue/647-File-objects-get-attribute-content-type-which-must-be-accessed-through-getattrCopy head branch name to clipboard