Support creating tables with column names that have period in them

Hello there!

Suggested change to wrap the param names in square brackets in the method build_param_list. This would enable us to auto-create tables with periods in the column names (i.e. for the sample R "iris" dataset for instance). However, I don't know if this would have adverse effects elsewhere in the code, so leaving it to you to figure out whether this is the right fix, thanks!

build_param_list <- function(query_params)
{
ps <- mapply(function(name, value)
{
type <- switch(class(value)[1],
"logical"="bool",
"numeric"="real",
"integer64"="long",
"integer"="int",
"Date"="datetime",
"POSIXct"="datetime",
"string"
)
paste(name, type, sep=":")
}, paste0('[', names(query_params), ']'), query_params)

paste0("(", paste(ps, collapse=", "), ")")
}