Better handling of empty tables without titles

Author: devashishdxt

cli-table/src/row.rs

@@ -112,7 +112,7 @@ impl Row for RowStruct {
 }
 
 /// Dimensions of a row
-#[derive(Debug, Clone, Eq, PartialEq)]
+#[derive(Debug, Default, Clone, Eq, PartialEq)]
 pub(crate) struct Dimension {
     /// Widths of each cell of row
     pub(crate) widths: Vec<usize>,

cli-table/src/table.rs

@@ -66,7 +66,13 @@ impl TableStruct {
 
         let row_dimension = match self.title {
             Some(ref title) => title.required_dimension(),
-            None => self.rows[0].required_dimension(),
+            None => {
+                if self.rows.is_empty() {
+                    Default::default()
+                } else {
+                    self.rows[0].required_dimension()
+                }
+            }
         };
 
         let mut widths = row_dimension.widths;