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 from v1.1 to v1.2 use these commits as a reference 91dac6f d440bd2

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 of Modular Admin: HTML version