android-daemon: Increase keep-alive timeout interval

The new option "keepalive_timeout" allows to define a larger interval for TCP
keep-alive packets. We increase this value to keep the device longer in sleep mode
and save some energy.
Merge pull request #67 from morgenroth/Increase-keepalive-timeout

Increase keep-alive time-out
daemon: Reduce pro-active exchange of routing data if PRoPHET routing is active

Prior to this patch, the PRoPHET routing implementation exchanges routing data with all
neighbors in a configurable interval. This pro-active behavior is removed now and replaces
through a reactive approach. Every time more recent PRoPHET routing data is necessary,
the routing module will trigger the handshake.