Improve feedback in Auras pane so violations are more clear

[amoeba]

Got some feedback from Discord that it's hard to figure out how to set Auras without violation Seer constraints:

The remaining four Seers are bitter rivals of one another. They do not relish teaching students who follow the guidance of another Seer. Though all the Seers accept (some begrudgingly) Nalicana’s hand in training, they will teach no student who carries the Aura of a rival Seer.

Note: You can only use one of these seers at a time. Choose carefully, as once you purchase an augmentation from one of the four, switching to another will result in the loss of both the luminance points and all augmentations from the previous Seer.

-- http://acpedia.org/wiki/Luminance_Auras