Use write/ss to output result in repl
Use write function if write/ss is not defined
Detect local and free index at compile time, not traverse time
Add bitwise operation functions (`logxxx` and `ash`)
Decide variable type in compile time, not traverse time
Store outer scope
Rename `len` to `length`
Disable code optimizer for a while
Change named let not to rely on the value of `set!`
Make `string` function to concatenate strings
Load test framework by tests themselvesf
Fix `remove-if-not`
Add test for boot and traverse
Remove empty declaration for `declaim` macro and native macro defining function
Remove macro table and store macros into global variable