main: Add a possibility to shorten the poll time to 0ms

Add a possibility to shorten the poll time in order to make it possible
to perform jobs registered with main_eachloopregister more frequently.

Change-Id: I6187d18b9432f092eab37417559fc3e3a13a1633
tests: Add compatibility with Ubuntu 12.04

Features missing on Ubuntu 12.04 platform:
pkill does not have --signal switch, insead one has to use -SIG
as first argument.
basename does not have -s switch, insead one has to specify suffix
as last argument.
nsswitch leaks in reading its configuration from /etc/nsswitch.conf.

Change-Id: Ieaa93352e00c6930cd8e4d842bb36b66adceea13