tests: some more vtimer -> xtimer conversions

[cgundogan]

No description provided.

[BytesGalore]

strange and OT, I cannot build it for native due to missing bits/c++config.h
travis seem not to encounter this problem, looks like a gcc version specific issue
T: gcc 4.6.2
Me: gcc 4.9.2

[cgundogan]

for all tests?

[cgundogan]

could you try it with docker?

[BytesGalore]

ahh, its an issue with x64/x32 libraries have missed to install the libstdc++

[miri64]

Just wanted to point out, that we got the same issue in RIOT-OS/Release-Specs#7 (comment) :-)

[BytesGalore]

I installed the current libs on a ubunty based system and it works for me:
sudo apt-get install g++-multilib
It pulled beside the g++ multilib package the libx32stdc++6 package plus the dev equivalents.
The tests for cpp11_* work for me.

[cgundogan]

I guess this is an ACK then? (:

[cgundogan]

if yes, merge at will

[BytesGalore]

So then, let it be ACK => and Go