returns more descriptive parsing error messages from load function.

Ref. #6

src/lib.rs

@@ -213,9 +213,24 @@ impl Fund {
         for line in buf_reader.lines() {
             let line = line?;
             let fund_info: Vec<&str> = line.split_terminator(":").collect();
-            let name: String = fund_info[0].parse()?;
-            let amount: f64 = fund_info[1].parse()?;
-            let goal: f64 = fund_info[2].parse()?;
+            let name: String = match fund_info[0].parse() {
+                Ok(name) => name,
+                Err(e) => {
+                    return Err(From::from(format!("while parsing {:?}: {}", config.fundfile, e)))
+                }
+            };
+            let amount: f64 = match fund_info[1].parse() {
+                Ok(amount) => amount,
+                Err(e) => {
+                    return Err(From::from(format!("while parsing {:?}: {}", config.fundfile, e)))
+                }
+            };
+            let goal: f64 = match fund_info[2].parse() {
+                Ok(goal) => goal,
+                Err(e) => {
+                    return Err(From::from(format!("while parsing {:?}: {}", config.fundfile, e)))
+                }
+            };
             funds.push( Fund{ name, amount, goal });
         }