Add location for snap version of Chromium (zserge#69)

This adds another location in which Chromium can be found on Ubuntu.

Fixes zserge#61

fix url regexp (zserge#52)

fixes invalid control character in URL error on Windows

Merge branch 'master' of github.com:zserge/lorca

return eval errors during export

add functions to export page or svg to pdf and png formats (zserge#22)

do not hardcode window class, let applications do it

add user local chrome installation path

Update README.md

add comment to Embed function