PE 08.04.2000

Included some scalar - vector operations in vec.h



Changes in vecadaptor.h:

SAB 30.01.2000:

I Want to use 

# define ARRAY(a)  TNT::Vector_Adaptor< std::vector<a> >

because I want to have consistency with TNT vectors, but also need STL
funktionality (push_back method).

Using push_back() on getVector leads to upredictable behaviour, since
push_back() changes the memory allocation.
--> added push_back() method to vector_adaptor.

Also un-commented begin() and end() methods. Which R. Pozzo had
commented out for compatibility with valarray.


SAB 22.03.2000: 
Added erase(iterator q) method