[FEATURE] Add iterator.keys ViewHelper

This mimics the iterator.values VH.
[TASK] Use // instead http to avoid errors/warnings with SSL - vimeo
[TASK] Use // instead http to avoid errors/warnings with SSL - youtube
Merge pull request #615 from xf-/youtubeProtocol

[TASK] Use // instead http to avoid errors/warnings with SSL - youtube
Merge pull request #616 from xf-/vimeoProtocol

[TASK] Use // instead http to avoid errors/warnings with SSL - vimeo
Merge pull request #614 from neufeind/feature/iterator-keys-VH

[FEATURE] Add iterator.keys ViewHelper
[TASK] Update hook definitions to new namespace classes
[TASK] Remove outdated TYPO3 6.0 travis builds
Merge pull request #618 from xf-/travisTypo3Update

[TASK] Remove outdated TYPO3 6.0 travis builds
[TASK] Make stdClass() use global namespace in AbstractImageViewHelper
Merge pull request #623 from soee/useGLobalNamespaceForStdClass

[TASK] Make stdClass() use global namespace in AbstractImageViewHelper
[BUGFIX] Ensure unique ids of nested menus
Merge pull request #627 from bjo3rnf/submenuid

[BUGFIX] Ensure unique ids of nested menus
[TASK] Pass mount point config to menu items
[TASK] Add maxW, maxH, minW, minH to ImageViewHelpers
Merge pull request #629 from cdfre/development

Add maxW, maxH, minW, minH to ImageViewHelpers
[BUGFIX] Fix broken flags argument in SortViewHelper

This commit fixes a bug in the SortViewHelper which prevented
the use of combined Flags like "SORT_FLAG_CASE | SORT_STRING" to properly
achieve caseinsensitive sorting.

- use arrayFromArrayOrTraversableOrCSV to split the sortFlags
- update documentation
- throw exception on unknown sortFlags
- fix sorting for empty string values
Merge pull request #626 from mneuhaus/sort_flags

[BUGFIX] Fix broken flags argument in SortViewHelper
Merge pull request #552 from bjo3rnf/mounty

[TASK] Proper rendering of mountpoints
[TASK] Throw appropriate exception and add test