Previously, the text padder media handler would assume that text always
started at time zero. This would work for VOD but would result with a
large pad at the start of LIVE content.
To avoid this, the text padder will use a bias to test whether or not it
thinks the content starts at zero. Right now the bias is set to be 10
minutes, but will later be configurable with a command line flag.
10 minutes was used as LIVE content will have much larger values and VOD
content should have much lower values.
Issue: #416
Change-Id: I07af15a577392fb030e36f052085cd4e667700e8
1600909c4b