To manage dev mode of pkgdown !!!

Closes #14

- fix missing details in load_crop_params doc

- add `read_CW8_CRO`
- integrate all examples in crop_params dataset
- refactor name of crop parameters
- handle markdown in roxygen doc

Closes #12

Closes #5

Closes #4

Fix #2

Fix #1

- Package initialisation
- crop parameters handling