solaris: test cases can't use grep -a The -a option to GNU grep isn't available when using Solaris grep. Replace the one use of grep -a in the testsuite with some in-line Python that does the equivalent, and add a check for grep -a in check-code.py.

revlog: pass node as an argument of addrevision This change will allow revlog subclasses that override 'checkhash' method to use custom strategy of computing nodeids without overriding 'addrevision' method. In particular this change is necessary to implement manifest compression.

revlog: extract 'checkhash' method Extract method that decides whether nodeid is correct for paricular revision text and parent nodes. Having this method extracted will allow revlog subclasses to implement custom way of computing nodes. In particular this change is necessary to implement manifest compression.

histedit: discard meaningless comment about 'hexlify node' Refactoring in 26b41a902195 made this comment meaningless. The node gotten by "discovery.findcommonoutgoing()" is hexlified in "between()" by "repo.set('%n::%n', old, new)".

histedit: add description about "histedit --outgoing" to command help Before this patch, there is no explicit description that argument is treated as the URL of the destination repository when "--outgoing" is specified. This patch adds description about "histedit --outgoing" to command help of it.

histedit: add description about basic histedit function to command help Before this patch, there is no explicit description that histedit edits changesets between specified ancestor and the parent of the working directory: users may notice it by error message "REV is not an ancestor of working directory". This patch adds description about basic histedit function to command help of it. This patch uses term "ancestor" instead of "parent", because it seems to be more suitable, and almost all (error) messages already use it.