* Define Instruction Set.
* WIP
* WIP 2
* Tests
* Working
* Bunch of other tests.
* WIP
* WIP
* Use Vec instead of VecDeque.
* Calibrate the limits.
* Clean
* Clean
* Another round of cleaning.
* Ignore traces.
* Optimize value stack
* Optimize a bit more.
* Cache memory index.
* Inline always instruction dispatch function.
* Comments.
* Clean
* Clean
* Use vector to keep unresolved references.
* Estimate resulting size.
* do refactoring
* Validate the locals count in the begging
* Introduce Keep and DropKeep structs in isa
* Rename/Split Validator into Reader
* Document stack layout
* Remove println!
* Fix typo.
* Use .last / .last_mut in stack
* Update docs for BrTable.
* Review fixes.
* Merge.
* Add an assert that stack is empty after the exec
* Introduce Trap struct.
* get_local can't fail.
* Add MemoryOutOfBounds trap.
* from_little_endian use slice instead of vec.
* MemoryAccessOutOfBounds for mem get and set.
* from_little_endian conversion can't fail.
* call_indirect traps.
* DivisionByZero and InvalidConversionToInt
* Use traps in value to convey an error
* select: int condition on stack top
* if: int condition on stack top
* Assert pops.
* Another protions of assert pops
* Introduce ValueStack
Also, hide FunctionContext and remove some stale code
* Traps in execution
* Make it compile.
* Check args before invoke.
* Document RuntimeArgs.
* Update host.rs
* Add rustdoc for Trap.