Menutree external dynamic link for Content updated

Including less stuff during getPages, otherwise too much API's get called where this is not necessary and increases load times !
Updated external dynamic links menutree with Clip

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | -
| Fixed tickets | -
| Refs tickets  | -
| License       | MIT
| Doc PR        | -

Clip publications are added to the available list of links one can dynamically add/generate in a menutree menu. I have this active currently already in Zikula Core 1.3.6 with the current Clip from Github. 

Of course the future of Clip is uncertain. So maybe this can be discussed before pulled.
Updated MenutreeApi for typo in comments

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | -
| Fixed tickets | -
| Refs tickets  | #1524
| License       | MIT
| Doc PR        |
Updated the MenutreeApi for lowercase method names

The method Content and Clip had uppercase names, adjusted.
Also adjusted MenutreeUtil call, which changed from Core 136 to 137
Merge pull request #1523 from espaan/patch-28

Menutree external dynamic link for Content updated
Merge pull request #1524 from espaan/patch-29

Updated external dynamic links menutree with Clip
Correcting icon name.
Merge pull request #1526 from shefik/login_icon

Correcting icon name.
improve js validation
add css display class to timepicker
Merge pull request #1527 from craigh/pickerfix

add css display class to timepicker
Merge pull request #1522 from cmfcmf/routing-profiler-enable

(Re-)enable WebProfilerExtraBundle routing data collector
Add support for PSR-4

Untested until rolled out by Composer.
Move example module to PSR-4
Merge pull request #1436 from drak/psr4

Add support for PSR-4
Correct paths for PSR-4 detection.
Implement shortcuts on entity names.
PSR-4 update
Increasing maxlength to match the groups table structure.
Merge pull request #1531 from shefik/group_name

Increasing maxlength to match the groups table structure.