add functions serverInfo() (exported) and setServerInfo() (not exported)

we can call shiny:::setServerInfo() in Shiny Server before launching an app, so that the app author can make use of the info to decide the behavior of the app
add a 'width' option to selectizeInput() and sliderInput() to specify the width of these widgets
roxygenize
validateCssUnit(width) for selectize and slider
add width to selectInput() as well
examples of the 'width' argument
roxygenize
upgrade selectize.js to v0.9.1 to fix the third issue in #428
make sure the `selected` argument never contains names; fixes #428
fix #220: the first entry is not necessarily a directory

in that case, we use dirname() on the first entry
Merge pull request #488 from yihui/bugfix/220

fix #220: the first entry in zip is not necessarily a directory
Don't print NULL to the console during renderPrint
Avoid black background when renderPlot doesn't actually plot
Validation error causes real errors to look like validation errors

The CSS class for validation errors was not being properly removed between different kinds of errors
Suppress validation errors from printing at console
Doc tweak to validation
Merge pull request #486 from yihui/feature/widget-width

Width of selectize and sliders
Merge pull request #489 from yihui/bugfix/428

Fixes #428
Merge pull request #492 from rstudio/bugfix/0.10misc

Miscellaneous bug fixes
Merge pull request #491 from rstudio/bugfix/validation-silent

Suppress validation errors from printing at console