add test for non-standard fonts
[db] map filenames to db indices instead of paths
store preprocessed font names with db
scan fontconfig dirs even though ``$OSFONTDIR`` is set

This is essentially what this change to the TL2011 version does:
    https://github.com/lualatex/luaotfload/commit/31530badb2681ff3423fe31f5eccf3d05fab1956#L2R657
in response to this issue:
    https://github.com/lualatex/luaotfload/issues/11
import from Context as of 2013-04-26
add draft lookup cache
improve request caching
add ``flush-cache`` option to fontdbutil
have flush_cache operate on names.data
import from Context as of 2013-04-26
install the new file: lookup in luaotfload.lua
drop scanning fonts.conf  in favor of `fc-cat`
Revert to old fonts.conf scanner because of ``io.popen`` restrictions

Apparently ``fc-cat`` would have to be whitelisted in TeX Live if we
want to rebuild the database during document compilation. Thanks Élie,
FOR POINTing that out to me.
reworked fonts.conf parser

improvements:

* works without ``io.popen()``
* scans attributes (like ``prefix``) as well
* abides by xdg config rules
* no line-based parsing
* parsing and interpreting the results are now distinct steps (-> less files open at one time)
* LPeg instead of string pattern matching
update fontconfig test
Import new font request parser

addressing https://github.com/phi-gamma/luaotfload/issues/4

incomplete for now, only handles file: and name: requests
Updating NEWS
unblacklist Apple TTC files

http://tug.org/pipermail/lualatex-dev/2013-April/001498.html
workaround for non-ascii cache file names
add fallback for specification name