better error message.
Fix typo in error message and add comment.
Add precheck and more detailed error message.
During the clean up when there is an error, do not override the error message.
Remove error about a variable not being defined.
Move the blocking buildbot run at the end.
Update doc about the buildbot
Add timming with cuda 5.5
Remove less informative error.

The python error is already set by device_malloc and it contain more information.
Add a timming with cuda 5.5
Do not print the memory profile when the information isn't available.
Fix condition following code review.
Merge pull request #1538 from nouiz/doc

Better error handling and buildbot