Basically, any character is now allowed after the shebang marker.
Closes#428.
Whitespace after the #! marker on shebang lines is authorized and
optional, as explained on Wikipedia's entry for shebang line as can be
seen from the extracts below :
> White space after #! is optional
and
> It has been claimed[20] that some old versions of Unix expect the
> normal shebang to be followed by a space and a slash (#! /), but this
> appears to be untrue;[21] rather, blanks after the shebang have
> traditionally been allowed, and sometimes documented with a space
bb567ba395