* Document inaccurate read-duration.
* --read-length CLI option + some code suggestions (11)
* Added --read-length CLI option
* Removed additional round for duration
- duration is rounded at calculation & when creating BitrateStatsSummary
* Edited logging in run_command function
- removed verbose input parameter
- added debug level log
* fix first packet's pts bug with --read-length
- calculates pts from next packet if value is missing
* minor code touchups
* Replaced read-length with read-start & read-end
* fix read-duration type and add to README
* fix first packet's duration bug
- occurs with --read-duration)
* edited for test case
- added check for 1st packet's duration type
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* Fix tests.