do some basic reformattings & add indentation

coubeatczech/wordpress-crowd-plugin#2
hide input elements in advanced > login mode

Hide input elements in advanced > login mode, that are not used when the
according radio button is select.

coubeatczech/wordpress-crowd-plugin#2
add mapping from crowd groups to wordpress roles

coubeatczech/wordpress-crowd-plugin#2
use the group mapping to roles during login

coubeatczech/wordpress-crowd-plugin#2
reuse the function `get_crowd_groups`

coubeatczech/wordpress-crowd-plugin#2
hide group mapping inputs on focus out

coubeatczech/wordpress-crowd-plugin#2
change checked in option to selected

coubeatczech/wordpress-crowd-plugin#2
adjust height of the advanced column

Because there are more items in it.
coubeatczech/wordpress-crowd-plugin#2
save option only when the relevant mode is selected

coubeatczech/wordpress-crowd-plugin#2
make it work when user in is more crowd groups

coubeatczech/wordpress-crowd-plugin#2
update readme

coubeatczech/wordpress-crowd-plugin#2