fix duplication in log output
prefer getwritablepath() to manual path building
systemize path handling ; improve cache write errors
fix names of bytecode compiled files
update NEWS
add mkfilelist (batch file hashing)
add filelist to makefile
add self test (--diagnose) to luaotfload-tool.lua
add git metadata to diagnostic info in luaotfload-tool.lua
rename mkfilelist to mkstatus
add github repo info to diagnostics in ``luaotfload-tool.lua``

this is still **experimental**. what to expect:

* the JSON parser in ``util-jsn`` needs fixing. currently it will
  fail if an API response contains escaped double quotes.
  see: <http://www.ntg.nl/pipermail/ntg-context/2013/074052.html>;

* requires the ``luasec`` module for https requests;

* may break in unexpected ways with connectivity problems, e.g.
  timeouts;

* errors not (yet) cumulative with the other diagnostics;

* not yet skippable with ``--diagnose``;

* for the time being API requests are unauthorized. acquiring a security
  token is a TODO.
make individual diagnostics selectable in luaotfload-tool.lua
add file permissions check to --diagnose option in luaotfload-tool.lua
[doc] describe --diagnose in manpage
add --diagnose to usage info of luaotfload-tool.lua
fix script name in manpage
add short usage message to luaotfload-tool
fix format specifier in diagnose printer
prioritize ``prefmodifiers`` oer ``subfamily``

follow-up to these previous modifications:

* https://github.com/phi-gamma/luaotfload/commit/fcdbafd0c86fdba08
* https://github.com/phi-gamma/luaotfload/commit/2938e7d63404f1d2e
* https://github.com/phi-gamma/luaotfload/commit/0e51cff12b24d264b

addresses https://github.com/lualatex/luaotfload/issues/108
i.e. "name:DejaVu Serif" does not resolve to the Condensed face anymore.
change mode of mkstatus to executable