add common crate

Signed-off-by: xermicus <cyrill@parity.io>

crates/common/src/lib.rs

@@ -0,0 +1,21 @@
+//!
+//! The compiler common library.
+//!
+
+pub(crate) mod base;
+pub(crate) mod bit_length;
+pub(crate) mod byte_length;
+pub(crate) mod eravm;
+pub(crate) mod evm_version;
+pub(crate) mod exit_code;
+pub(crate) mod extension;
+pub(crate) mod utils;
+
+pub use self::base::*;
+pub use self::bit_length::*;
+pub use self::byte_length::*;
+pub use self::eravm::address::*;
+pub use self::evm_version::EVMVersion;
+pub use self::exit_code::*;
+pub use self::extension::*;
+pub use self::utils::*;