Support locking of directory entries

Moves the locking algorithm from file entry to file system entry.

Fixes whatwg#137

index.bs

@@ -109,7 +109,7 @@ specifications do not need to bother implementing [=/file system entry=]'s
 
 Issue(101): Make access check algorithms associated with a FileSystemHandle.
 
-Each [=/file system entry=] has an associated <dfn for="file system entry" id=entry-name>name</dfn> (a [=string=]), 
+Each [=/file system entry=] has an associated <dfn for="file system entry" id=entry-name>name</dfn> (a [=string=]),
 a <dfn for="file system entry">lock</dfn> (a string that may exclusively be "`open`", "`taken-exclusive`" or "`taken-shared`")
 and a <dfn for="file system entry">shared lock count</dfn> (a number representing the number shared locks that are taken at a given point in time).
 
@@ -125,7 +125,7 @@ Issue: We should consider having further normative restrictions on file names th
 never be allowed using this API, rather than leaving it entirely up to underlying file
 systems.
 
-A user agent has an associated <dfn>file system queue</dfn>  which is the
+A user agent has an associated <dfn>file system queue</dfn> which is the
 result of [=starting a new parallel queue=]. This queue is to be used for all
 file sytem operations.