Minor correction
Merge remote-tracking branch 'mongodb/master'
Fixed typo "video of audio" to "video or audio"
Update source/reference/operator/centerSphere.txt

Code didn't use $within which results in an error.
merge: correction
merge: typo correction
merge: correction with geo operator
Update source/faq/concurrency.txt

Simple typo - word missing in the JS operations paragraph
SERVER-7994: clarifying that timeLockedMicros may be longer than total operation length.
SERVER-7994: updating timeLockedMicros
merge: minor fix