Add calibration documentation to python docs

[Gesner Passos]

Add the session of calibration to the python sphinx generated documentation.

[Gesner Passos]

Tester:

Do not forget that #7387 must be passed first. Do not test this before.

After building mantid, you must build the python documentation.

make -j4 sphinx-html

So, open the python documentation inside the sphinx/html/index.html file. It must have a new session and a link called Calibration. Foolowing this link you should see the documentation of the calibration framework and some pictures as well.

[Gesner Passos]

Configure sphinx to parse the tube calibration

re #7437

Changeset: bce375ab87e954bd969df36473cf6214f8660798

[Gesner Passos]

Improve the connection of the parameters and its usage

re #7437

Changeset: 46a6193f7071bf5afa7ede1af2b647bd4a3c45e5

[Anders Markvardsen]

For information #7387 has been tested

[Wenduo Zhou]

There is some conflict during merging feature/7437_doc_calibration.

git merge --no-ff origin/feature/7437_doc_calibration Auto-merging Code/Mantid/scripts/Calibration/tube.py CONFLICT (add/add): Merge conflict in Code/Mantid/scripts/Calibration/tube.py Automatic merge failed; fix conflicts and then commit the result.

[Gesner Passos]

Merge remote-tracking branch 'origin/master' into feature/7437_doc_calibration

Conflicts:

Code/Mantid/scripts/Calibration/tube.py

It was necessary to merge master into 7437 to solve conflicts.

re #7437

Changeset: 3039afca224fedb5d0cf8afaf00272c8483a6d27

[Gesner Passos]

I will not wait for checkbuild, because there were changes only at documentation (commented code). So, it is ready to be tested.

[Martyn Gigg]

Merge remote-tracking branch 'origin/feature/7437_doc_calibration'

[Stuart Campbell]

This ticket has been transferred to github issue ​8283