Implement Try Method 

It is a fairly common pattern to see `CanGetChar` closely followed by a call to the following methods.

```
PeekChar
GetChar
PeekAheadChar
```

So I think it could be beneficial to have a Try variant of those methods.

```
TryPeekChar
TryGetChar
TryPeekChar
```

It also allow us to the "cache" the character, thus not paying the penalty of multiple call to `PeekAheadChar`
