* perf: use a separate icons.svg file
This splits icons into inline and non-inline. The inline ones are high
priority; the rest go in an icons.svg file.
* create SvgIcon.html
* determine inlined svgs at build time
* fix: update to latest sapper
fixes#416
* fix error and debug pages
* requestIdleCallback makes column switching feel way nicer than double rAF
* add export feature
* add better csp info
* workaround for sapper sub-page issue
* clarify in readme about exporting
* fix now config
* switch from rIC to triple raf
* style-loader is no longer used
* update theming guide
