Re-export file source type markers (fixes #91)

Author: mehcode

src/file/mod.rs

@@ -10,6 +10,9 @@ use value::Value;
 pub use self::format::FileFormat;
 use self::source::FileSource;
 
+pub use self::source::string::FileSourceString;
+pub use self::source::file::FileSourceFile;
+
 #[derive(Clone, Debug)]
 pub struct File<T>
 where

src/lib.rs

@@ -64,6 +64,6 @@ mod value;
 pub use config::Config;
 pub use env::Environment;
 pub use error::ConfigError;
-pub use file::{File, FileFormat};
+pub use file::{File, FileFormat, FileSourceFile, FileSourceString};
 pub use source::Source;
 pub use value::Value;