adjust indent
remove trailing spaces
Merge pull request #2160 from nobu/space

Space
fix condition for the rest of input

the input must rest the length of a string to be peeked at least.
fixes parse error at embedded documents by string eval, and `-e`
command line options.
fix embedded documents

tabs are allowed after `=begin` and `=end`.
raise `SyntaxError` if no =end is found.