Added nomination searching.

[CrimsonTautology]

Integrated logic from my nomgrep plugin. Allows players to filter the nomination list by sub string. For example typing !nomsearch koth_ would generate a list of all koth maps on the server. Or if you know you want to play koth_ashville, but are unsure of what version is on the server you can type !nomsearch ash to filter the menu by all maps containing "ash". This is great for servers that have huge map lists and you don't want to press 9 a bunch of times to get to the map you want.

[powerlord]

I totally forgot this was still out there. I'm not sure if I should actually try merging it (I've made a bunch of changes in the past year) or just redo it.

[MitchDizzle]

This is pretty interesting, a feature that I would like, as giving search terms to the nominations helps servers with huge map lists. Perhaps making it an addition to the nomination command instead (!nominate dust2). If there are multiple maps containing the search parameters then it will be added to a menu and sent to the client, however if 1 matches then it should just add the match to the nomination. This would be easier than remember a map called 'mg_some_custom_map_v3_hotfix_a1' and have to type it out fully in order to add it to the nominations.