Format doc (from devtools to energy_functions)

Devtools, distributions and energy_functions
Format documention in expr/basic

Includes important changes to the docstring of symGivens2
Format documentation in expr
Format doc in gui (and format)

The change in format is very minor.
Format documentation in linear
Display multiple levels of indentation correctly
Remove tabs
add all files
text fix
Set self.input_space for FlattenerLayer too.

Signed-off-by: Axel Davy <axel.davy@ens.fr>
Implements get_input_space for FlattenerLayer to avoid confusion.
added test
format fix
Npz dataset support for targets
FlattenerLayer: Remove redundant field.
Fix math in expr/basic.py
Add "WRITEME" for some parameters
Modified track_version.py (to import models)
Fix typo in internal/dev_start_guide.txt
Fix typo in config/yaml_parse.py