setup: add a function to test header files

setup: split "hasfunction" to test arbitrary code The next patch wants to test include files.

rebase: add flag to require destination In some mercurial workflows, the default destination for rebase does not always work well and can lead to confusing behavior. With this flag enabled, every rebase command will require passing an explicit destination, eliminating this confusion.

update: add flag to require update destination In some mercurial workflows, the default destination for update does not always work well and can lead to confusing behavior. With this flag enabled, every update command will require passing an explicit destination, eliminating this confusion.

mq: reject new patch name containing leading/trailing whitespace We could create a patch of such name, but it wouldn't be processed properly by mq as parseseries() strips leading/trailing whitespace. The test of default message (added by b9a16ed5acec) is no longer be useful so removed. This issue was reported as: https://bitbucket.org/tortoisehg/thg/issues/4693/

shelve: rename stripnodes to nodestoprune Since we are introducing obs-based shelve, we are no longer stripping temporary nodes, we are obsoleting them. Therefore it looks like stipnodes would be a misleading name, while prune has a connotaion of "strip but with obsolescense", so nodestoprune seems like a good rename.

shelve: add an ability to write key-val data to a new type of shelve files Obsolescense-based shelve only needs metadata stored in .hg/shelved and if feels that this metadata should be stored in a simplekeyvaluefile format for potential extensibility purposes. I want to avoid storing it in an unstructured text file where order of lines determines their semantical meanings (as now happens in .hg/shelvedstate. .hg/rebasestate and I suspect other state files as well). Not included in this series, I have ~30 commits, doubling test-shelve.t in size and testing almost every tested shelve usecase for obs-shelve. Here's the series for the curious now: http://pastebin.com/tGJKx0vM I would like to send it to the mailing list and get accepted as well, but: 1. it's big, so should I send like 6 patches a time or so? 2. instead of having a commit per test case, it more like a commit per some amount of copy-pasted code. I tried to keep it meaningful and named commits somewhat properly, but it is far from this list standards IMO. Any advice on how to get it in without turning it into a 100 commits and spending many days writing descriptions? 3. it makes test-shelve.t run for twice as long (and it is already a slow test). Newest test-shelve.r runs for ~1 minute.