Araq/Nimrod — pull request #1341 by def- (2014-07-09 16:47:20+00:00)
Title: Add reversed proc

A more efficient reverse if you need a new seq instead of working inplace. Only traverses the input array once and writes the output seq once. Offers better performance:
```nimrod
var c = @[0]
for i in 1..10000000:
c.add(i)

# 2.6 s
for i in 0..10:
var d = c
reverse(d)

# 1.5 s
for i in 0..10:
var d = reversed(c)
```