feat(@ohif/extension-vtk): Add visible crosshair lines to MPR mode

re OHIF#562

feat(@ohif/extension-vtk): Add oblique rotate button to MPR mode

re OHIF#563

feat(@ohif/extension-vtk): Update app to include basic MPR with VTK (O…

…HIF#557)

feat(i18n): Add ability to internationalize the application and its e…

…xtensions (OHIF#526)

* i18n basic setup

* i18n - extension extraction

* Creating spanish translation

* i18n - extension extraction

* i18n - Multiple languages overrides

* i18n - Multiple languages overrides

* remove yalc react-viewerbase

* use t prop from withTranslation

* fix typo

* Exports provider and HOC to be used by any application without install I18Next libraries

* i18n - Documentation

* i18n - Adding Provider to non Admins

* i18n - Documentation for i18n

* i18n - Documentation for i18n

* Configures hif-vtk-extention to use ohif-i18n for translation and include load more locations

* update i18n documentation

* add language detector lib

* fix text

* WIP - using yalc for react-viewerbase

* remove unused switch language buttons

* Update yarn.lock

* Merge branch 'master' of https://github.com/OHIF/Viewers into feature/i18n-basics

# Conflicts:
#	extensions/ohif-vtk-extension/package.json
#	extensions/ohif-vtk-extension/rollup.config.js
#	extensions/ohif-vtk-extension/yarn.lock
#	package.json
#	src/App.js
#	src/components/Header/Header.js
#	yarn.lock

* Adding language detector as Peer Dependency, its not working inside the rollup bundle.

* Upgrading i18next version.

* Language Detection implementation, bug fixes related to i18n and debugger helper added.

* Updating i18next documentation.

* i18n implementation - Adding final packages

* small fix

* i18n implementation - Fixing up vtk-extension's  packages

* i18n implementation - Fixing up translations

* i18n implementation - Updating yarn.lock

* fix require.context bug

* udpate ohif/i18n version

* i18n implementation - Updating yarn.lock

* i18n implementation - Removing bad image from docs

* i18n implementation - Removing ROI from translations

* i18n implementation - Fixing CineDialog translations

* update i18n package

* fix conditional

* update i18n

* fix conditional

* update @ohif/i18n

fix(StudyBrowser): Remove transform to fix drag/drop positioning for …

…thumbnails (OHIF#548)

Merge pull request OHIF#514 from dannyrb/fix/hotkeys

Fix/hotkeys

fix(initWebWorkers): Fix duplicate slashes for web worker paths (OHIF…

…#527)

Merge pull request OHIF#524 from dannyrb/fix/quick-toolbar-edits-and-…

…version-bumps

Fix/quick toolbar edits and version bumps

Merge pull request OHIF#518 from OHIF/bump-react-viewport

fix(react-viewport): Bump react-cornerstone-viewport

fix(extension-dicom-microscopy): bump microscopy and ohif-core deps, …

…scope package name (OHIF#513)