enable laxbreak option in jshintrc to comply with our coding guide lines

Our JS coding guide lines want to have operators in split control structure lines on the left hand sides. Rightfully so for better readability: http://doc.owncloud.org/server/7.0/developer_manual/app/general/codingguidelines.html#id2

However, our JS Hint check results in such errors when applying this rule:

```There seems to be a bad line break before &&.```

See it in thus scrutinizer result:  https://scrutinizer-ci.com/g/owncloud/core/inspections/49a82234-76de-43d5-88fa-ee97b49985aa/issues/files/apps/user_ldap/js/settings.js?status=new&selectedAuthors[0]=blizzz%40owncloud.com&orderField=path&order=asc

The only possibility to make jshint pass is to enable [laxbreak](http://www.jshint.com/docs/options/#laxbreak). 

I have no idea what to do about the prior »You should not use mixed whitespace characters (tabs and spaces).«.

Opinions? @PVince81 @DeepDiver1975 @MorrisJobke others?