closes #213: merge the documentation of runUrl(), runGithub(), and runGist()

removed the port and launch.browser arguments, and used ... instead
move runGist() and runGithub() after runUrl(), and merge their descriptions into the description of runUrl()
let download() fail in this case (ref=NULL); since ref='master' by default, if the user provides another value, he/she is expected to have read the documentation
the name variable is not used anywhere
closes #427: runGitHub() can accept "username/repo" in its first argument
the message is not very useful, given that download() will emit a message
subdir=NULL is the default of runUrl()
typo: flowPanel --> flowLayout
Merge pull request #514 from yihui/doc/news-flowLayout

typo: flowPanel --> flowLayout
Bump version to 0.10.0
Fix timing issue with random seed test on windows
assuming all the input R scripts are UTF8 encoded

ui.R, server.R, and global.R
make sure the HTML content is encoded in UTF8
make sure JSON messages are always encoded and decoded with UTF8

- per @jcheng5's suggestion, RJSONIO::fromJSON(encoding = 'UTF-8') actually works (no longer need my markUTF8 function)
- removed the global option 'shiny.transcode.json'
the cachedSource() function is not used anywhere, so perhaps we can remove it
UTF8 encoding for runApp(list(ui, server)) as well
Bump to development version number
Merge pull request #516 from yihui/bugfix/windows-encoding

Fixes #136: I18N support for Windows
Merge pull request #507 from yihui/doc/runUrl

Merge doc for runUrl(), runGist(), and runGitHub()
a news item for #516