Merge pull request #1 from lebarsfa/master

First commit.
Merge pull request #2 from lebarsfa/master

Friend functions that did not need to be friend moved outside the class ...
Merge pull request #3 from lebarsfa/master

Bug fixes and additions.
Merge pull request #4 from lebarsfa/master

Bug fixes and additions.
Merge pull request #5 from lebarsfa/master

Modifications related to interval::Intersect(), interval::IsEmpty(), operators, using namespace std, and other minor additions and modifications.
Merge pull request #6 from lebarsfa/master

Harmonizations with interval_adapt related to operators.
Update README.md
Update README.md
Update README.md
Update README.md