Migrated from Bower to NPM + Browserify

Dependencies

Added browserify 16.2.3
Added browserify-ngannotate 2.0.0
Added gulp-buffer 0.0.2
Added vinyl-source-stream 2.0.0
Updated angular 1.4.1 -> 1.7.5
Updated angular-ui-router 0.2.15 -> 1.0.20
Updated jquery 2.1.4 -> 3.3.1
Updated semantic-ui 2.0.0 -> 2.4.2
Updated showdown 1.2.1 -> 1.8.7
Updated sweetalert 1.0.1 -> 2.1.2
Updated validator 10.8.0 -> 10.9.0
Downgraded gulp 4.0.0 -> 3.9.1
- This is because we currently depend on semantic-ui, which does not support gulp 4.0.0
Removed bower(!!!)