hgweb: more ui fiddling

hgweb: fix hgweb_mod as well as hgwebdir_mod

hgwebdir_mod: use fake termwidth to avoid mod_wsgi's wrath

termwidth: move to ui.ui from util

help: improve description of update --check

store: encode first period or space in filenames (issue1713) - Mac OS X has problems with filenames starting with '._' (e.g. '.FOO' -> '._f_o_o' is now encoded as '~2e_f_o_o') - Explorer of Windows Vista and Windows 7 strip leading spaces of path elements of filenames when copying trees Above problems are avoided by encoding the first space (as '~20') or period (as '~2e') of all path elements. This introduces a new entry 'dotencode' in .hg/requires, that is, a new repository filename layout (inside .hg/store). Newly created repositories require 'dotencode' by default. Specifying [format] dotencode = False in a config file will use the old format instead. Prior Mercurial versions will abort with the message abort: requirement 'dotencode' not supported! when trying to access a local repository that requires 'dotencode'. New 'dotencode' repositories can be converted to the previous repository format with hg --config format.dotencode=0 clone --pull repoA repoB

demandimport: fix an obscure corner-case. Python's __import__() function has 'level' as the fourth argument, not the third. The code path in question probably never worked. (This was seen trying to run Mercurial in PyPy. Fixing this made it die somewhere else...)

keyword: enforce subn method via boolean switch There are only 2 patterns to choose, and so far only 1 case where kwtemplater.re_kw.subn is applied on data read from the working directory: when recording added files. With this change the code reflects more closely the boolean character of the switch and underlines the special case.

keyword: fix weeding of expansion candidates when recording Rearrange tests to check this, i.e. that there are changes in other files, not only the recorded one.

copies: don't detect copies as "divergent renames" (For the purposes of this patch copy is defined as a rename where the source continues to exist.)