Otreeutils

* `surveys` module:
* added missing "change" triggers when checkboxes are selected in Likert table via clicking/touching the table cell
* added a check to require the `survey_definitions` argument to be a tuple in `create_player_model_for_survey`

* `surveys` module:
* added option `table_repeat_header_each_n_rows` to `generate_likert_table()`
* fixed problem where form options like `form_help_initial` were ignored

* `surveys` module:
* add several options to `generate_likert_table()` to adjust display and behavior of Likert tables
* allow non-survey form fields on survey pages

* pages derived from `ExtendedPage` may set `debug_fill_forms_randomly` to `True` so that when visiting the page, its form is filled in with random values (helpful during developement process)
* `surveys` module: all columns in a Likert table now have the same width. The width of row header (first column) is 25% by default and can be changed via `table_row_header_width_pct`

* `surveys` module: field labels can now contain HTML (HTML is not escaped and will be rendered)

* added class attribute `custom_name_in_url` for `ExtendedPage`: allows to set a custom URL for a page (instead of default class name)
* several improvements in the `surveys` module:
* added `other_fields` parameter to `create_player_model_for_survey` to allow for additional (non-survey) fields
* corrections when using surveys module in several apps on the same server instance
* added option to specify conditional field display via JavaScript
* added option to specify form label suffix
* added option to specify field widget HTML attributes
* added option to use custom choices (`use_likert_scale=False`) in `generate_likert_table`
* alternating row colors and hover for likert table
* added new `scripts` module:
* properly set up your command-line scripts to work with oTree by importing the module
* export of hierarchical data structures from collected data