Ast spanned<T> refactoring, renaming: crate, local, blk, crate_num, crate_cfg.

`crate => Crate`
`local => Local`
`blk => Block`
`crate_num => CrateNum`
`crate_cfg => CrateConfig`

Also, Crate and Local are not wrapped in spanned<T> anymore.

src/libsyntax/util/parser_testing.rs

@@ -33,7 +33,7 @@ pub fn string_to_parser(source_str: @str) -> Parser {
     p
 }
 
-pub fn string_to_crate (source_str : @str) -> @ast::crate {
+pub fn string_to_crate (source_str : @str) -> @ast::Crate {
     string_to_parser(source_str).parse_crate_mod()
 }