IE8/9 file upload

Demo: https://demo.shinyapps.io/09_upload/

You can use a sample CSV file, say `write.csv(iris, 'iris.csv', row.names = FALSE)`.

![screen shot 2014-09-25 at 4 52 20 pm](https://cloud.githubusercontent.com/assets/163582/4413712/9f637652-4509-11e4-9abe-33d03979c3f0.png)

The required version of mime is on CRAN now, but this should not be removed until shiny 0.10.2 is on CRAN. Similar thing applies to R6 below. The reason is `install.packages('shiny', dep = TRUE)` cannot install all dependencies until the info is available on CRAN. The problem can be solved by `devtools::install_deps(dep = TRUE)`, though.