Removed Iterator template internal range checks
* the standard doesn't require iterators to perform range checks
** performing range checks on each iterator move operation hurts performance
*** not to mention the additional memory requirements...
* even if one would want to perform range checks the implementation used in the Iterator template is unsatisfing
** simply discarding the operation is bad
** responsibility to perform range checks is placed on the calling code
*** this code had to perform range checks anyway - i.e. in loops
* added no-throw assert for Buffer templates operator[]
** analog to the previously introduced operator[] check for the Container template
Added const Buffer member method overloads
* altough the previous implementation of these methods was marked as const they weren't in the sense that they couldn't be used to modify the underlying values
** but this is what const should express!
* added new static method _constructValue_ to the Tuple template
** this was needed to enable value_type constuction from const-pointers
** sadly a internal const_cast was needed as the Mapper template currently doesn't offer construction from const base pointers
* begin() and end() BufferIterator construction methods are still marked as const
** according to what I have written above they shouldn't be as they offer the possibility of value modification
** => const BufferIterator template specialization is needed to fully implement constness in the Buffer template