Opm 139 wellinfo eclrestart

Extended EclipseWriter to write wellinfo to restart files. Added unittest and corresponding testdata.

The restart files are extended with wellinfo so that they can be viewed in Resinsight. 
If trying to open opm-generated restart files with ECLIPSE - this will crash and burn. The restart files does not contain enough information for ECLIPSE to parse them. 

The (small) libecl_well library are linked in and used in the unittest - this is because Resinsight is using this library when loading restart files  - so a good test will have to use this library. 

This pull-request is dependent on the following pull requests to be merged and deployed first: 
- ERT PR: https://github.com/Ensembles/ert/pull/661 (extended ert library to write well info to restart files)
- OPM-parser PR: https://github.com/OPM/opm-parser/pull/372 (extended schedule class with methods to support EclipseWriter)

The code was compiled with gcc-4.6.1 and tested on red hat 5. 





Why do you need a free store operation here?  Would it not be simpler to "just" use something along the lines of
```C++
ecl_rsthead_type rsthead_data = { 0 };
rsthead_data.sim_time = timer.currentPosixTime();
// and so on
```
and then passing a pointer to `rsthead_data` into the functions that need such pointers while keeping the C++ API as mostly "reference-to-const"?