Made STKM use different particles as jetpack spew

The change makes STKM be able to use other particles as what comes out when it fires the rocket boots. Some elements even alter the feel of flight, for example solids generally make turning very _very_ snappy and powders make stabilizing work utterly well. 

There are two modes of using it:  
1. Setting stickman's tmp value to 1 (via console) and then using the head's element as the spew
2. Setting stickman's tmp value to 2 (via console) and then using its own tmp2 as the element ID. Old TPTScriptInterface automatically converts element names to IDs so assigning an element to tmp2 will work without issue.