* jk/grep-binary-attribute:
grep: pre-load userdiff drivers when threaded
grep: load file data after checking binary-ness
grep: respect diff attributes for binary-ness
grep: cache userdiff_driver in grep_source
grep: drop grep_buffer's "name" parameter
convert git-grep to use grep_source interface
grep: refactor the concept of "grep source" into an object
grep: move sha1-reading mutex into low-level code
grep: make locking flag global