Grammar bugs fix

[yshinya6]

I've found some conflicts in between yacc and nez. For example, following import declarations are conflicted.

• yacc ImportDeclaration : IMPORT PackageName ';' ;
• nez ImportDeclaration = "import" { $(Name ('.' Name)*) #ImportDecl}

Define complete syntax and correct these conflicts.

[yshinya6]

Modified by b98afa0e29147c78d5f916fdf6322578088e1d9f