test-convert-darcs: don't let $HOME/.darcs pollute the test environment

convert: refactor sink initialisation, to remove hardcoding of hg We also introduce options to explicitly set the source and destination repository types. Improve testing of corner cases a little.

convert: add default constructor for converter_sink

convert: make contents of "extra" dict available from sources, for sinks. This breaks hash preservation for hg->hg conversion, as each converted change gets a convert_revision item added to its extra dict. Ugh.

convert: rename convert_svn to svn_source

convert: report errors more meaningfully if run with --traceback

osutil: Solaris build fix

Fix build error with Sun C compiler.

osutil.c: use strncpy instead of strncat

findcopies: fix rename bug We've fiddled with this line several times, and an old bug has reappeared from it. Let's take a peek at the history. The original "or" (rev 3674, in 0.9.2 and 0.9.3): http://www.selenic.com/hg/rev/9103dab96093 Then I changed it to an "and" to fix a bug (rev 4304): http://www.selenic.com/hg/rev/4787e2b0dd03 Then for reasons now lost in the mists of time, I dropped half (rev 4399): http://www.selenic.com/hg/rev/93652499bed3 Then we added back the "or" (rev 4416, in 0.9.4): http://www.selenic.com/hg/rev/bb1800a7d7e1 So it seems it ought to be "and".