shinytest2 v0.2.1

• Fixed request from CRAN to correct C++11 problems in web checks (#326)

• Fixed bug where compare_screenshot_threshold() did not safe guard against errors thrown by screenshot_max_difference() (#276)

• Fixed bug where preview overflow did not have length of 1 (@cpsievert #291)

• Better support for saving global variables for a Shiny server function (#307)

• Better error message when both app.R and server.R are found (#284)

• Force JS code to be a character for {glue} support (#288)