[Dcmlib] reverse_iterator

[Mathieu Malaterre]

JP,

	Welcome back !

	Just a quick note, std vector support the notion of bidirectional 
iterator (you can start from either the start or the end). For example:

http://www.informit.com/guides/content.asp?g=cplusplus&seqNum=93&rl=1
-> Section 'Reverse Iterators'

This is generally nicer than a while, and I believe it helps the 
compilers to do optimization (I need to check on that).

Mathieu