Android cpu optimizations refactors

Detailed comments on each commit.

After these modest changes and refactors, CPU usage dropped 30% on android devices in an environment with over 8 devices using cling concurrently.

These are suggested updates we've implemented to our production code, if there's the need for discussion we'll welcome it and we'll be glad to receive pull requests back if necessary so that the cling community benefits from the CPU/Energy savings of these proposed optimizations.

There's one related dependent commit to the seamless repository, which I'll be sending a pull request soon after this.
https://github.com/gubatron/seamless/commit/210874629b14c3c6fe7a788a95f7b1c887b74b3f