fix stdin message handling & specs

closes #1386
Pass correct HOME env into chroot

Without this patch the logstash isn't able to start on Debian 7 when using file input, as both HOME and SINCEDB_DIR aren't set in chroot.
Merge branch 'pr/1343'
closes #1343
initial spec for pipe input

removed logging

fixed encoding header

closes 1385
replace json parsers with JrJackson and Oj
refactored timestamps with new Timestamp class
closes #1434
fix external command invocation
changelog for 1.4.2
Fix missing require
Fix typo