Make parse return a list of parse errors

Which basically just means unmatched lines.
There are no descriptive errors, at least for now, but at least this
gives you the option to display warnings or errors.

inifile.lua

@@ -59,8 +59,12 @@ function inifile.parse(name, backend)
 	local comments = {}
 	local sectionorder = {}
 	local cursectionorder
+	local lineNumber = 0
+	local errors = {}
 
 	for line in backends[backend].lines(name) do
+		lineNumber = lineNumber + 1
+		local validLine = false
 
 		-- Section headers
 		local s = line:match("^%[([^%]]+)%]$")
@@ -69,6 +73,7 @@ function inifile.parse(name, backend)
 			t[section] = t[section] or {}
 			cursectionorder = {name = section}
 			table.insert(sectionorder, cursectionorder)
+			validLine = true
 		end
 
 		-- Comments
@@ -77,6 +82,7 @@ function inifile.parse(name, backend)
 			local commentsection = section or comments
 			comments[commentsection] = comments[commentsection] or {}
 			table.insert(comments[commentsection], s)
+			validLine = true
 		end
 
 		-- Key-value pairs
@@ -87,6 +93,11 @@ function inifile.parse(name, backend)
 		if key and value ~= nil then
 			t[section][key] = value
 			table.insert(cursectionorder, key)
+			validLine = true
+		end
+
+		if not validLine then
+			table.insert(errors, ("Line %d: Invalid data found '%s'"):format(lineNumber, line))
 		end
 	end
 
@@ -96,7 +107,7 @@ function inifile.parse(name, backend)
 			comments = comments,
 			sectionorder = sectionorder,
 		}
-	})
+	}), errors
 end
 
 function inifile.save(name, t, backend)