Meta filter

Usage
```
<meta-filter>(<getter>, <value>)
```
For instance

```
Filter f = lessThan(descriptionGetter, L"Hello World");
```
yes, that will work. but the pointer-to-member syntax is VERY ugly:

```C++
class A {
    void lol(Task& e);
}

decltype(&A::lol) ptr = &A::lol // => (void A::*typeOfMember)(Task&)
ptrToA->ptr(task)