Modifications towards making code compile on win

Modifications to make code compile on windows

It should compile with win32, but for several reasons does not yet work on my 64bit win8: I did not yet manage to get cppunit build 64bit code and also we are triggering a VC++ compiler bug in "Realse" mode. In "Debug" mode things should build as the bug is related to optimization routines.

Further changes following
well the safest and simplest solution imho is just to separate declaration & definition right on the spot:
```
template <typename T>
NIXAPI T convertToSeconds(const std::string &unit, T value);

template <typename T>
T convertToSeconds {
...
}
```
If there are no objections for now I will pursue this solution.