Update Shoebox, migrating from Gson to Kotlin Serialization

Updates Shoebox, which now uses Kotlin serialization rather than Gson.

Note that this will be a breaking change for most code that uses Shoebox. Gson was no-longer recommended for use by its creators, and Kotlin Serialization has the advantage of avoiding runtime reflection - which makes it significantly faster.

Upgrade to Kotlin 1.4.0 and Ktor 1.4.0

Update Kweb's various dependencies to their latest versions.

Improve configurability of render container element

See #151

Make render() container element tag configurable

0.7.19

tidy up var name

Mitigate problem where Fomantic plugin is used in multiple Kweb instances

0.7.18

bump version for release

Resolve issue with using some nested HTML tags within others

See #148.

Move keyspecificevent to plugin, bugfixes

Many thanks to @marad once again for #144 and #146

Simplify event handling API

Many thanks to @marad for this simplification of Kweb's event handling API - see #142 and #129 for more information.

Move event-related extension functions to kweb.* namespace

0.7.14

optimize imports

Redesign event mechanism to make it more general and support document-level events

Many thanks to @marad for this contribution, see #129 for discussion and #141 for final pull request.