Try country-dependent jQueryUI localization files

When we load the jQueryUI, we should check if there's a file with full
locale code (eg ui.datepicker-zh-CN.js) before trying to load the file
with language-only code (eg ui.datepicker-zh.js).
Better representation of method parameters

- Let's try to retrieve the constant names (so that the output won't
  contain installation-dependent constant values, for instance
  DIR_FILES_THEMES instead of '/git/concrete5-5.7/web/application/themes')
- Correctly represent 'empty' values: 0, false, empty arrays are now
  represented as they are (and not as null or empty strings)
Call getDefaultValueConstantName just once
Translate Search in user points
Started working on the search index attributes
Got the code working to run the "Index Search Engine - All" function, properly adding the collection search index attributes
Fixed namespacing to allow for class specification I previously removed
Moved column exists check logic
PSR-2 Formatting of files I touched
Add getPageTemplateDisplayName
Translate style customizer

...and fix some jshint warnings.
Translate spectrum
Fix assets minification and combination

- set correct namespace for CssMin (it's \CssMin)
- assets with urls starting with / are relative to DIR_BASE, not to
  DIR_APPLICATION
- to retrieve the class of an asset: let's use get_class, since
  concatenating AssetType + 'Asset' does not contain the class namespace
Fix Facebook authentication type
\ should not be allowed in an attribute handle
Add link to facebook apps page
Merge branch 'searchIndexAttributes' of https://github.com/ExchangeCore/concrete5-5.7.0 into ExchangeCore-searchIndexAttributes
Fixing some tests
Merge branch 'ExchangeCore-searchIndexAttributes'
Merge branch 'master' of github.com:concrete5/concrete5-5.7.0