Bar plot with whiskers and significance bridges

Produces a bar plot with whiskers above each bar and bridges between user-specified bars

This file allows for the creation of bar and whisker plots with significant/insignificant relations indicated between bars by bridges plotted above the whiskers. It takes three arguments: the height of the bars, the length of the whiskers, and the identity of the significant bar pairs to be 'bridged'. 'Extra significant' bridges are indicated by dots; these are specified by the user in the bridge argument.