Bug fix: resolution check on macthing states

I found the following bug:

```
Egison Version 3.3.12 (C) 2011-2014 Satoshi Egi
http://www.egison.org
Welcome to Egison Interpreter!
> (define $g (pattern-function [] ^<nil>))
> (match {1 2 3} (list integer) {[(g) 1]})
egison: hs-src\Language\Egison\Core.hs:(514,1)-(515,62): Non-exhaustive patterns in function topMAtom
```

I found that bug of *resolution check on matching states* causes this bug.
The following matching state should be regarded as *resolved* matching state:

```
MState (...) (...) bindings1 [MNode (...) (MState (...) (...) bindings2 [])]
```

and return `bindings1 ++ bindings2` as bindings of whole the matching state.