For some reason cmake errored out if Likwid was not found on that
platform.

Before the change, the DIR was set to 'g++-4.9__wo_' for each compiler. This should fix this...

The first change is required to allow for
```
Configuration(std::string key, bool value)
```
calls, and the second one is required for
```
Configuration(std::vector<std::string> keys, std::vector<long int> values)
```

[common.configuration] drop obsolete ctor

*sigh*

# Conflicts:
#	dune/stuff/test/common_string.cc

Conflicts:
	.travis.yml

following 576fd81493af76d7be365402b58dcdfa9dae83df, refs #62

I got a compile error with clang 3.7.0 for this one, maybe you want to take
a closer look, @renemilk?