modified indent rules
removed duplicated lines
modified indentation of {if,let}
modified indentation
fixed indentation about parentheses
fixed indentation
modified indentation of {bar,let-in}
modified order of indentation element
modified indentation of parenthetic block
fixed last return-value
slightly modified
merged with default ftplugin
removed unnecessary ftdetect
modified indentation about block comment
fixed indentation at comment line
fixed indentation
added new feature:

  * insert language-extensions as LANGUAGE pragma automatically
    when new file created
fixed typo