Merge pull request #779 from vsevolod127/master

Add more classes to TreeItem elements
insert method for menu bar. allows menus to be dynamically added.
    - all changes related to events in datefield, merged into one commit
Merge pull request #781 from mahomahomaho/dfevents2

Datefield events: introduce object handlers as a (companion to y/m/d triples)
[#781] simplifications/cleanups/correctness

- python vim plugin (trailing whitespace! yarg!)
- avoid single line compound expressions (`except x: y`, `if x: y`)
- y/m/d redundant; *ALWAYS* `fireDateSelectedEvent(object)`
- `hasattr()` calls `getattr()` internally; simplify
- convert Calendar y/m/d input to `date()` immediately
Merge pull request #780 from gpitel/menubar_insert

insert method for menu bar. allows menus to be dynamically added.
[#780] `insert()` methods traditionally return `None` in python... consistency is king!
- locale definition fix
- a bit of padding and align
Merge pull request #784 from mahomahomaho/locales-encoding-fix

UTF-8 encoding definition fix
Merge pull request #783 from mahomahomaho/mf-align-spacing

(a bit of padding and align) this is fine for now; ideally though, we should be adding more classes + CSS
remove superfluous print statement
merge `output/css.d/*` into one `output/base.css`
merge `output/css.d/*` into one `output/base.css` [css.d/datefield.css]
merge `output/css.d/*` into one `output/base.css` [examples/cssauto]