Many compiler warnings due to the new Lifecycle API

[felixdivo]

#722 introduced quite a few warnings, see this recent build from master.

They all seem to be quire easy to fix though (mainly warning: variable ‘currentContent’ set but not used).

[wayneparrott]

@felixdivo Thx.
My BAD! I've gotten too used to seeing compiler warnings with node-gyp build.
I'll submit a fix PR asap.