Don't null out the throughput timer, just reset it
It's not necessary to null out the throughput timer and it could be dereferenced if the src is changed while a seek is still "in-flight". Resetting it ensures it is stopped and zeroed and it can be garbage collected along with the rest of the HTTPVideoProvider. This was causing errors in videojs-contrib-hls when the source was changed quickly after a seek was requested.
Merge pull request #125 from videojs/hotfix/throughput-null

Don't null out the throughput timer, just reset it
added cleanObject function to recursively sanitize objects before passing to externalInterface.call
make tabs not spaces
updated VJS in package.json
Merge pull request #127 from mmcc/hotfix/clean-metadata-and-such

Added cleanObject function to sanitize metadata
Added changelog items for #125 and #127. Also cleaned up some other changelog formatting differences.
Release 4.5.1