Fixes #22: Fixes style issues

position.go

@@ -6,7 +6,7 @@ import (
 	"fmt"
 )
 
-// position within a TOML document
+// Position within a TOML document
 type Position struct {
 	Line int // line within the document
 	Col  int // column within the line
@@ -18,6 +18,8 @@ func (p *Position) String() string {
 	return fmt.Sprintf("(%d, %d)", p.Line, p.Col)
 }
 
+// Invalid returns wheter or not the position is valid (i.e. with negative or
+// null values)
 func (p *Position) Invalid() bool {
 	return p.Line <= 0 || p.Col <= 0
 }