[client] mastery page error if name is a capitalized version of a different page.

It took me a really long time to discover the source of this bug, but here we go.

I designate my masteries by their trees, so for example I have page named "ferocity CUNNING", one page named "FEROCITY cunning", one page named "ferocity RESOLVE", etc.

The error appears to be caused by giving a mastery page a capitalized version of another mastery pages name. Usually, if you give mastery pages the same name, they add a number at the end to differentiate. However, if they have a difference in capitalization, the client pops the following error instead: http://puu.sh/nt5ST/8f4f423464.jpg. Once the error pops up, any time I click "save" or swapped to a new mastery page, the error would pop up again. This continues until I restart into the client.

Any changes I make to mastery pages after the error has occurred do not properly save. As long as the client remains open, the page appears to be in proper order in the mastery tab and in champ select. However, if I enter a game, any changes I made to the page do not stick. If I had made a new page, I do not get the benefit of any masteries. If I restart the client, any changes made do not stick, and newly made pages either disappear, or are emptied of all data. This failure to save affects all pages, whether or not they have a shared name.

It is possible to stabilize a set of pages with a shared name, but it's fiddly and I'm not exactly sure what I did to make it happen. I have since put numbers at the end of my pages to prevent the bug.