add links to examples in shiny dev center
a news item for the optgroup feature
warn against the byte order mark if exists; fixes #545
deal gracefully with elements that have no computed style available
update comment with more specific browser notes
Merge pull request #550 from rstudio/bugfix/offscreen-shinyapps

Deal gracefully with elements that have no computed style available
add explanations of skipping *nix when checking encoding, and point to the shiny dev center article
Remove caTools dependency

Instead, use base64 encoding function from httpuv
one more check before we use UTF-8: see if there are embedded nul's
Add custom version of selectize.js to work around Firefox bug

This is a workaround for issue #550. This version is based on selectize version 0.9.1.
Merge pull request #549 from yihui/bugfix/utf8-bom

warn against the byte order mark if exists; fixes #545
Merge pull request #553 from wch/hidden-selectize

Add custom version of selectize.js to work around Firefox bug
Bump version to 0.10.1
Merge pull request #552 from rstudio/no-catools

Remove caTools dependency
Merge tag 'v/0/10/1'

Shiny 0.10.1 released to CRAN
Bump to development version number
Copy over progress code from shinyIncubator
Get session without needing to pass it in
Add Stack ref class
Put progress stack in session object