Migrate fork fixes to v1.4.10

PLBCK-140
Fix for CC not being shown when seeking to 0.
Cherry picked cbsinteractive#5 to v1.4.10.

PLBCK-129
Closed captions shown out of order on 608/708 captions.
Cherry picked the following commits to v1.4.10.

• a734fe08fe15898233b9511c7d07bf7272722627
• 288ed30b5faade0d64cc48ae4621816af77b3159
• be5665eccbe93b3e97e6161bc70e48e72df0f5c5
• 4a6a68caa5e2ba7e1e231dae67880aba597f4bca