Gulp update and install errors fixes

• Updated gulp version (thanks to@mon-compte-github )
• Fixed npm installation node gyp errors
• jQuery vesion update

Update Bootstrap version to 4.0.0

• Updated bootstrap version to v4.0.0
• Remove bower form the project
• Migrate bower dependencies to NPM
• Update dependency modules versions
• Update docs

Responsive utils fixes

Fixed#73

Update to Bootstrap 4 beta#69

For migration fromv1.1 tov1.2 use these commits as a reference91dac6fd440bd2

Other Changes

Added livereload#68
Add sub-menu support to sidebar#18
Open menu on mobile#7
Added .editorconfig
Readme Updates

Added support for node 8
Update gulp-sass version

Bootstrap version update to v5 alpha

Fix issue#17
Readme updates

Closed issues

• #3: Notification icon counter is cut.
• #4: Item editor page: images sorting.
• #5: Demo pages should have links "download", "documentation", "view on GitHub".
• #6: Get rid of global functions.
• #8: Sparkline charts hover labels are broken.
• #9: Sometimes charts are not redrawn on theme change.
• #10: Texts centering in auth dialogs.
• #11: Add LICENSE.
• #12: Logout link is wrong.
• #14: Add dist html beautifier.
• #15: Items list overflow issue on mobile.

This is the first release ofModular Admin: HTML version