Disable hooks if instrumentation is detected

Detect instrumentation at application binding.
New static flag in XposedBridge which acts as a "kill switch" for
user installed mods - that flag is enabled when instrumentation is
detected. My understanding is that once the initial hook (the one detecting instrumentation) is fired, the VM was already forked so altering a static variable doesn't affect other past or future processes.

If you are instrumentating an application, you're likely to already have the source code, hence won't be needing to alter the behavior using Xposed.
Also, current Xposed implementation doesn't handle the way instrumentation loads classes from another classloader.

http://forum.xda-developers.com/showpost.php?p=41688269&postcount=1517