Added #if TargetWin32 wapper around method
Modified VBWFS module

- Added code for IPmt. (Confirmed results against Excel.)
- Where given, the type parameter will be set to 1 when <> 0.
- Added UnitTests as hidden protected method.
- Call VBWFS.UnitTests from App.Open.

Updated version to 3.0.1.
Merge pull request #11 from ktekinay/master

Modified VBWFS module
Merge pull request #10 from arbp/master

Merge changes