fix: throw a descriptive error when an undefined attribute is used for a...

... component

Fixes #253

I'm afraid that this is the best I can think of doing based on what I can see being available in the context where the error occurs. Obviously we can't provide the original line number:column as a template is compiled but what is kind of not nice is the fact that we can't (?) provide the impacted component name as it is a function and its constructor seems to be an anonymous function... 

@b-laporte, are there any other sources of data that I'm not aware of and we could use for better error reporting? 
The impacted component name is in this.info, so to be in line with other error messages, this one could be changed to:
` throw new Error(this.info + ' The attribute "' + etc`