Allow void expressions, capture stdout, use dedicated parser for multiple statements per line

Just some possible fixes for issues I found while playing with drepl (some of these are in the issue tracker, #2, #11).

Adding a dedicated parser inherited from stdx.parser allows to have multiple statements per line, but does now force the use of a semicolon to end expressions. 

It also allows detecting the auto variable declarations to do the re-write into 
```typeof(init); shared static this() { etc. }```
I haven't implemented the re-write because I can't test it. For some reason, when running the console.d example, declaring variables (int a; ) and then using them (a += 5; ) fails with dlopen complaining it can't allocate memory in static TLS. Function decls and such work OK. 

take or leave :)