[js:core] implementation of theme changer

[johnfort]

Plz, add themesBasePath, themes, themes in preference and author (maybe parse comment in css (if exits)) of theme in about the software.

[johnfort]

next request of fix (see screen)

[johnfort]

@nao-pon Plz, delete:

html.push(sep);
html.push('

'+fm.i18n('icons')+': Pixelmixer, Fugue, Icons8

');

I'm not use this icon...

[nao-pon]

@fortcms

I'm not use this icon...

They are included in the distribution package and can not be deleted.

[johnfort]

@nao-pon Create new tab "Theme info" similar as 'Help'

[nao-pon]

@fortcms There is a tab "Theme".

[johnfort]

@nao-pon I thought you would do differently.
Drop-down list of themes and their instant applyed. Then the theme photo is not needed!
And the tab in the "about topic" in the "help".

[nao-pon]

Please try https://github.com/nao-pon/elfinder-theme-manifests .

[johnfort]

i will test it tomorrow