Support traditional keyswitches as inputs

[capnspacehook]

Adds the ability to trigger inputs on keyswitches. Previously this could be approximated by the input note target, but that required the note to be held. This allows notes that are simply played once and not held to act as keyswitches, telling Foresight that the articulation was switched and to influence output settings.

I'm happy to update the wiki and add documentation for the new config settings if this gets merged as well.

Example config for Orchestral Tools Berlin Orchestra Violins 1:

<foresight version="2" name="OT BO Violins 1">
    <settings>
        <latency>150</latency>
        <keyswitches boundary="lower">C1</keyswitches>
        <keyswitches boundary="upper">A1</keyswitches>
        <range boundary="lower">G2</range>
        <range boundary="upper">D6</range>
    </settings>
    <input>
        <switch target="KS_C1">
            <switch target="legato">
                <case equals="0">Sustain</case>
                <case equals="1">Legato</case>
            </switch>
        </switch>
        <switch target="KS_C#1">Sustain</switch>
        <switch target="KS_D1">Staccato</switch>
        <switch target="KS_E1">Spiccato</switch>
        <switch target="KS_F1">Pizzicato</switch>
        <switch target="KS_G1">Tremolo</switch>
        <switch target="KS_A1">Trill</switch>
    </input>
    <output>
        <tag name="Legato">
            <set target="legato" />
            <set target="start">-150</set>
        </tag>
        <tag name="Sustain">
            <set target="legato" />
            <set target="start">-50</set>
        </tag>
        <tag name="Staccato">
            <set target="start">-30</set>
        </tag>
        <tag name="Spiccato">
            <set target="start">-30</set>
        </tag>
        <tag name="Pizzicato">
            <set target="start">-20</set>
        </tag>
        <tag name="Tremolo">
            <set target="start">-100</set>
        </tag>
        <tag name="Trill">
            <set target="start">-50</set>
        </tag>
    </output>
</foresight>