Various small fixes in scan

Release preparation

Try to use the old interface and silence part of the printed stuff.

Add ARM architecture check for Raspberry Pi

[MRG]Gpuarray eye

added numpy.random.choice function

Fix rng empty shape

the choice function

Fixes in conv3d2d for python 2.4

numbers implementation

After additional checks introduced in gh-1578, some code that was
potentially problematic became unreachable. This commit removes it.
This makes gh-1345 obsolete.

Add test for that case

msvc9 compatibility