Opens the url in user's default browser.
If the flags parameter contains wxBROWSER_NEW_WINDOW flag, a new window is opened for the URL (currently this is only supported under Windows).
And unless the flags parameter contains wxBROWSER_NOBUSYCURSOR flag, a busy cursor is shown while the browser is being launched (using wxBusyCursor (not implemented in wx)).
The parameter url is interpreted as follows:
Returns true if the application was successfully launched.
Note: For some configurations of the running user, the application which is launched to open the given URL may be URL-dependent (e.g. a browser may be used for local URLs while another one may be used for remote URLs).
See: wxLaunchDefaultApplication() (not implemented in wx), wxExecute() (not implemented in wx)