BHoM Tkinter bug fixes and improvements

[Felix-Mallinder]

Issues addressed by this PR

Closes #213

General upgrade to the BHoM Tkinter tools, prompted by bugs in aesthetic and functionality issues identified in dependant toolkit(s).

Overview:

• on_change callback implemented at toplevel, in bhom_base_widget, for consistent action of widgets in a form
• Alignment improvements; for consistent use of align / sticky etc.
• improved validation logic across some widgets
• Upgrades to the cmap selector to work with custom colour collections
• general bug fixing (in response to copilot review / testings)

Test files

~\Python_Toolkit\Python_Engine\Python\tests

Changelog

Additional comments

[Felix-Mallinder]

@BHoMBot check required

[bhombot-ci]

@Felix-Mallinder to confirm, the following actions are now queued:

• check code-compliance
• check documentation-compliance
• check project-compliance
• check core
• check null-handling
• check serialisation
• check versioning
• check installer