Modify speaker key behavior

[ddspringle]

Currently the system assigns a unique random key (e.g. AS7eY4vfG) to speakers which is then in turn used by the system to show the speaker information (e.g. http://acpspeakers.com/si.cfm/RHcKQjLB).

It would be desirable to instead either have the speaker choose their speaker key by entering it manually (e.g. HappyCoder, etc.) and checked for uniqueness, or as an alternative have the speaker key derived from the first and last name of the speaker (e.g. dspringle) and made unique as required (e.g. despringle, dspringle1, etc.).