don't precompile the kick script; instead to force the engine to pause just evaluate something

This technique seems to work more reliably. Instead of precompiling a script when attaching, and reusing that, just evaluate an expression directly. Various versions of webkit don't seem to support precompilation (no Debugger.compileScript). Here we just use Runtime.evaluate. In addition, this fixed a bug in Chrome because Chrome doesn't seem to reply with a packet when using `runScript`, at least sometimes.

Previously the debugger would be stuck in a paused state in startup, or easily get stuck in a weird state, depending on the device. This seems to make it behave rather well on iOS and Chrome.

Now I can get to the real stuff.