Added sphinx files
Added needed config files
Fixed submodules
Try to supress bundle doc warnings
Added .gitignore
Updated travis config
Revert changes
Added CMF
sparse checkouts
Update documentation
feature #3328 [WIP] Travis integration (WouterJ)

This PR was merged into the 2.3 branch.

Discussion
----------

[WIP] Travis integration

| Q   | A
| --- | ---
| Doc fix? | no
| New docs? | no
| Applies to | all
| Fixed tickets | #2722, #3332

##### Todo

 - [x] Using sparse checkout
 - [x] Update contributing docs
 - [ ] Squashing commits
 - [ ] Activate Travis hook (@fabpot)

Commits
-------

37eb137 Update documentation
8dec729 sparse checkouts
b6f693e Added CMF
b1d9e62 Revert changes
6cad008 Updated travis config
c515613 Added .gitignore
85b1b02 Try to supress bundle doc warnings
f3cb8b1 Fixed submodules
71a2ff4 Added needed config files
d312683 Added sphinx files