Improved handling of ill-definded problems in coinf, especially in find_limits.
Returns now inf if no limit can be found.
moved examples out of the test directory.
adding the files
Merge pull request #67 from Tillsten/coinf-improvements

[BUG] Improved handling of ill-definded problems in coinfidence.py
Merge pull request #68 from danielballan/models

Model addition, predefined subclass Models, and lots of unit tests
Merge pull request #69 from Tillsten/master

[TST] moved examples out of the test directory.
DOC: New docstrings for utilfuncs, inherited by their Models. Also updated docstrings for Model and fit()
ENH/TST: fit result has handy attributes. Includes associated tests.