wip: new method to declare and manage GUI params

each parameter should now be an instance of GuiParam. this will ease the
addition and removal of parameters from the interface.
widget type will be inferred inside the class
small reordering on combobox
all gui params in a method, more dev on the class

- method guiparams generate an attribute with all the gui parameters.
- update save_settings and load_settings to use guiparams.
parent init now using super

changed the parent initialization in order to use super.
save/load main params working, removed deprecated

. save and load main parameters tested and working on mac.
. main_window group pars not using the class GuiParams.
. removed deprecated functions: load_settings and save_settings.
. restore defaults button clears the settings file.
. retrieve data name on start up (if loading previous session).
new version of save_gsimcli_settings() with GuiParams

issues: needs to update the dependencies values; empty() not working
properly.
deprecated save_gsimcli_settings()’s previous version.
GuiParam.load forcing value type, debugging in progress
. GuiParam.load forcing value type according to widget type
. fix some GuiParams instances
. debugging save/load running on linux
fix GuiParams instances, save and load QSettings adapted to GuiParams
. set default QSettings codec to UTF-8
. fix GuiParams instances dependencies with lambda's
. save_settings with two purposes: save to self and export
. dependencies checked on save and load
. load_settings does not require self.settings, receives a QSettings
instead
. deprecated load_setttings_iniformat
. GuiParam dependencies must be GuiParam's or callable's
. fix GuiParam.empty() and renamed to has_data()
. pylist_to_qlist accepts a single object and turns it into a list
fix saving empty gsimcli params, removed deprecated's

. fix save_gsimcli_settings don’t save when param has no data
. deprecated’s removed:
- load_settings_iniformat
- save_gsimcli_settings
- save_gsimcli_params
Merge branch 'guiparams'