Automatic nesting into running transactions in the same repository. This associates a transaction handle with a given repository object, and any additional calls to start new transactions reuse that transaction. For the 2700 patch import run, this brings the system time down from 1m20s to 50s, mostly by skipping backups of the dirstate file. (note, this patch does not change hg import to use the nested transaction, mq is the only user right now)

Fix bash_completion on Solaris TK Soh noticed that the awk that ships with Solaris doesn't allow you to define new functions. According to http://www.shelldorado.com/articles/awkcompat.html it looks like it also doesn't have some other stuff that we were using, like deletion of an array element and gsub. Rewrite the parsing of hg --debug help to work around that. This version doesn't filter aliases that are simple abbreviations for debug commands (not a big problem, since there are none right now).

refactor the dodiff optimization