This commit renames the `vec_access()` and `vec_size()` methods to match
the ones in the `DenseVector` facade class, that is `operator[]()` and
`size()`.

Closes #3

Gcc 4.6 cannot generate default move constructor for classes containing a
DynamicVector because there is no move constructor and the copy constructor
is non-trivial.
This patch fixes this, by adding move semantics.

Add template parameter for the allocator of the internal std::vector.
All constructors are adadpted to forward a user chosen allocator
to the internal data stroage (std::vector).

DynamicVector. Inheritance doesn't work for template specialization
lookup... not that this specialization isn't necessary, if you are
using FieldVector<T,n> via the interface class DenseVector< FieldVector<T,n> >

[[Imported from SVN: r6174]]

  few cases, where CRTP really makes sense!)
* type infroamtion is provided via DenseMatVecTraits

[[Imported from SVN: r6171]]

[[Imported from SVN: r6135]]

[[Imported from SVN: r6131]]

[[Imported from SVN: r6130]]