* SFC parseComponent pads content with spaces
when `{ pad: true }` is provided. That is, all content is converted to
spaces. Previously, each line was truncated to "//". The new padding
method works better with character-oriented tools that calculate
positions by distance from the beginning of the file instead of by line
number.
* Made parseComponent's pad support "line" | "space"
Also still supports true for backward compatibility. True is the same as
"line".
* Pass attributes to parseComponent
* Edited source in the right place, added test
* Back out changes made to the generated compiler build file
* Add a few more checks
This allow to use other block appart from `template`, `script` or
`style` in the SFC parser. This allows such things as writing tests or
examples directly into the SFC file. Those are meant to be handled by
programs others than vue-loader like vue-play.